I haven't exerienced what you've been through but I guess if you were after some practical strategies for coping if you really do HAVE to go I might suggest:

1. Set a specific time limit on how long you are going to be at a party and communicate this to your hosts. (ie. yes we will come but we will have to leave at 3pm).
2. Set a strategy of who you will be most comfortable talking to at the gathering and try to spend more of your time with those people. (For me, I would hide out in the kitchen, under the pretense of helping).
3. Congratulate yourself on when you survive 1 hour of each party or when you get home and have survived!
4. Remind yourself that going to the party is going to make other people happy, even if you are not happy. Eg DD might have a good time, relatives will enjoy seeing you.

If your DH isn't being supportive, then I would avoid discussing the matter with him too much at this point.

Hope these strategies help!

Ruth