Personally I would go! Sorry to be so blunt.
This is very definitely YOU time. You cannot be expected to deal with his childish behaviour and lets face it many of them just revert to being children (as you can probably tell I am on my own!!)
You need to have your own space to do as you wish, even if that means lying in bed all day crying, so be it.
whatever YOU want to do, do it.
BUT just be sure to keep some cherished friends, or close family in the loop and TALK to them when you feel down. Although you don't think so it is good to talk.
I have been through some horrendous times and I now know that keeping it bottled up inside helps absolutely noone expecially you.
I really really wish you well.
tsn xx