Hi Steve,
One thing that helped me to overcome is to realize that no matter how cold, unfeeling, selfish, and egocentric I might perceive a friend or a family member to be, it was not that other person's "fault" if I felt guilty. I learned to forgive, which freed me to give from my own heart, as I felt led to give to them, with no strings attached.
Some people might say, "expect nothing, then you'll never be disappointed". Well, I do believe that unmet expectations are the cause of a great amount of grief and there may be some truth in that, but it sounds to me like a pretty hopeless way to live, so instead... I determined to expect the best from myself and let the chips fall where they may (at the same time, making sure to keep my hands outta the other guy's bowl of chips... in other words, let him carry his own baggage ~ I have enough of my own, tyvm).
The short of it is ~ I think that there's a strong element of manipulation involved when we serve others in order to appease our own sense of guilt, so I gave it up. Now when someone asks me to do something for them, I consider my options and, when necessary, simply say, "I won't be able to help you with that, but I certainly hope you'll be able to get it worked out". No further explanation needed.
I've heard it said that insanity is doing the same exact thing, in the same exact way, time and time again, yet expecting different results. Best way I found to get off that merry-go-round you seem to be on is to forgive the "offender", stop demanding that he meet my expectations, while forsaking any notion that I can ever give enough to get him to meet my needs, and focus on being a person of integrity. I hope this helps.
Hope