Tay,
I would wait until the relationship moved along before mentioning anything of the sort to M. You are more than entitled to adult time, and that is what I would say to M. I think, with kids, they do not need new people in their lives as parental figures unless it is a SURE thing. So, if things go along and you decide H is the one for you and you want to cement the relationship, at that point, I would talk to M, but not before. He has had plenty of upheaval with the lack of father, psycho granadma and so on. Now, you are the person he will look up to and pattern after. My personal opinion is that relationships should be kept separate from children unless they are absolutely in the final form you will choose for your family. Honestly, were something to happen to my husband, I would focus on the kids solely. If I had a personal relationship, I would keep it wholly separate, unless the person were a perfect fit and I felt he could take part in our family. And that would take a lot of proof for me.
H sounds very nice and it is super that her kids like to play with M. The game night sounds like so much fun!!!
Yes, sharing the information with your brother would be nice.
Again, all my personal beliefs...
Love, Beth