Thank you to everyone who's spent time giving me their opinions on this - they've all been very helpful. Me and my husband talked things out last night after he came back from his 'walk' (sulk), so we're OK, now, which is good, but I want to understand this to prevent it happening again.
There's been so many suggestions in the posts so far, I'll try to reply to them in bits:
Ami,
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I think that it started on HER part,but you may unconsciously 'taken the bait" "
Yes, I think I responded to something that she did, and it surprised me. Not sure yet quite what it was that I reacted to, though.
"
I think that she may have been threatened by you(for whatever reason).I think that it was a "power play" situation.It sounds like she was having a 'turf war" with you.If not, she is simply a rude person "
We both find her rude, but I think she DOES feel threatened by me, but my husband thinks I'm over-reacting.
Bean,
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Your husband may be less objective than you because it is his son? Perhaps he doesn't want to think or talk badly of them?"I think you've hit the nail on the head here. He deals with it by not talking about it, even though last night he admitted that he is very worried that his son is getting long-term entangled with this woman who, he thinks, will drop him when she finds out what she REALLY wants to do. Hints dropped by her over the weekend include going to New Zealand to get a job as a doctor. My stepson has a good job here in the UK, as an electronics engineer, so he doesn't need to emigrate to find work, but he might follow her...neither me or my husband would like that, really.
The thing about the incident with the request ' can I have a Fresh apple?' is that it was said to me, AFTER the others had gone out of the kitchen..so they didn't hear it (or other comments over the weekend about food). So my husband says 'all that just went over my head. Can't you forget it? It's no big deal'. Well it is to someone who's had anorexia, because control games over food are VERY important, and I see what she's doing, I just don't know why. You reject a person by rejecting their food. It's very basic.
Lighter,
Thank you for saying this: "
I don't think you were seeing things that weren't there. "
You wrote: "
Now, I'm not sure why you and your husband argued. It seems as though you vented to him about how you were feeling and he didn't validate you?"Yep, that's right.
There wasn't an argument with the girlfriend and stepson. It was just a bit 'cool' while they were here, and a bit superficial, conversationally. I think that's a shame, considering we don't see them to catch up with what they're doing very often.
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Did your husband jump on you for rude behavior?" No, I was very 'restrained' while they were here ...possibly TOO restrained, as he didn't hink there was a problem *at all* until AFTER they'd gone, when I dissolved into tears.
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If your husband simply wants a peaceful day of visting with his son, once a year, and to pretend he likes the girlfriend then I can understand that too. " Yes, so can I. I'd like that, too, even if we don't like his choice of girlfirend.
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He shouldn't throw you to the wolves though. " I don't think it was that strong, but, usually he understands, and occasionally he doesn't. When that happens it surprises me and upsets me, as usually we are very close. Sometimes, I just have to accept that he's got a willy and I haven't.

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You can choose to be proactive in the future about the visits"
I suggested that, and that's where the argument seemed to start... I get the 'he's MY son' and I'LL arrange the visit' That's what is annoying - I just seem to get it presented as a fait accompli, and I just spend the time in the kitchen.
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but your husband will always love his son and want to see him. " Yes, but I think he realises (as I do) that his son might emigrate because of this girlfriend, and I think this might be at the root of all this.
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I'd like a little clarification about what you argued with husband about, specifically? " It seemed to be that he'd wanted to 'get over' the uncomfortable visit as soon as possible by spending Sunday doing 'something nice' (re-wiring the hifi system was what he chose to do), whereas I needed to sit on my own and think things through, which, once he realised what I was mulling over, he decided that that was 'stupid' and 'a total waste of a day'. I told him my feelings were valid, but that they were just different from his. But still valid. He kept saying I 'should' think this and 'should' think that, and it niggled me. He's not usually like that.
Stormchild,
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you weren't visited. You were Dad's Hotel" Yep, sure was. I don't like it when people 'visit' but then let it be known that they have planned what they'll do while they're in your area...but it doesn't include *you* going to the places with them.
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the girlfriend... may feel insecure bc of not being employed... she may be unemployed bc she acts like this on her interviews." Yes, I'm not sure why, but she DOES come across as insecure.
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Too bad, if so, that she has to make you into a competitor. " Yes, because I'm obviously not, although I did used to get on well with him (still do), but perhaps it's the *relationship* between me and my husband VERSUS her and R's that is so obviously different, and it's THAT that she feels uncomfortable about. We are very happy, on the whole, and I have heard via my husband's first wife that my stepson wants kids, but that H doesn't. That must cause huge arguments at times between them.
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And the business about accusing you of seeing an N under every wastebasket... oh dear. " Yes, I don't know how to be *less well-informed* than I am, especially when it's helping me so much. I dunno, men and their little insecurites!! I don't think you're being sexist, I think you're being honest.
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getting a bit... above yourself." is exactly how I'd describe my husband's response last night, and that's very out of character for him.
What you've said has helped, Stormchild, but I don't have all the answers yet, either!
CB,
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I'm sorry the visit was hard. It was probably hard for your husband, too and he doesnt know how to deal with both of your disappointments at the same time. " Yes, I think that's it...he does try to 'hold the hurt' for both of us, sometimes.
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Nice to hear that he went out to take a walk and think about it. " Yes, and he came back with a rose for me - isn't that sweet? How can I be angry with him for long? I think this is why we get so upset when we're upset...it's just so unusual for us.
Hops,
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Could it be that this triggered defensiveness and tension (along with their inconsiderate behavior)? I was wondering if perhaps her presence reminded you of a terrible time in your own life when food ruled you. Maybe she's a frightening reminder?"
Yes, she is. I have had so many screaming matches in the past (mainly teenage years) with my Nmum. Food is such a battleground. My husband said that I have felt this terror (his word) of people coming into our house and ignoring my boundaries before, which is true. I have had so many boundaries violated in the past, to have someone *staying* in my house, and feel that they are walking all over me, and I don't have the power do stop it, does frighten me. And no-one else seems to see it like that. A soon as they'd left, I felt like getting the disinfectant out. I went round the house almost 'patting' things to make my mark again - very basic, instinctual stuff.
Innerquest,
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when offspring visiting their parents, they feel to use it as accommodation is a given, and they can use their time anyway suits them. When they are back, it is like turn into 10 year old, they won't think about social ettequtes. " I think this is very insightful. I have never had to put up with the selfishness of a two-year-old in the house. But when people get to be 30, I expect them to behave like adults, whatever the relationship. Is that too much to ask?
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the girl is silently controlling people, anyboday spent long enough with, would be tranined on tipytoes or run away. They are not loud, rude, agressive, they do their thing politely, only the target can feel it. Other people won't see it." Yes, quite.
I'd like to try levelling, but at the time it was happening, I couldn't quite believe it was happening, so I didn't respond in time.
Anyway, I've had lots of responses to think about, and I feel a lot better now! I'm just glad I've got this forum to go WAAAAHHHHH!!!! on occasionally.
Thank you
Janet