Cheesyt, if you want to go to the party then go. Remember, this is about you. Not about W, MIL, etc. All about you making a decision about what would make you happy.
If you don't want to go, then find a fun GAL activity to take it's place! No need to spend an evening indoors when you could be out having fun!
Hang in there Cheesyt!
Me39 M11 : T13 D9 BD 5/31/16 In House S until 6/21/17 Divorced 10/5/18