I think definitely brave the holiday!
I'm sort of ok overall, though right now I'm crying in bed, which isn't how I planned to spend my day (dcs with h today).
Last time, it was such a struggle every day, but I knew I had to continue because my h was being a total nightmare, real crazy ex stuff, worse than when we had been together.
Then he suddenly stopped being horrible and turned all charming and helpful, and I stupidly decided he was alright actually and we should get back together to end the pain and the struggle of separating, and for the children's sake. I was on my knees, terrified to make any decisions, could barely continue. So I asked him to try again, we agreed ground rules - he would go for counselling (his dr had already referred him), we would both go to Relate- and he moved back in.
One month in, I found he had been seeing someone else, this was what turned the nice guy act on. He lied about her, I searched his computer, he still lied. Somehow we carried on. I wasn't strong enough to end it again. He didn't go for counselling. We did go to Relate, which helped a bit.
Nearly a year later, after endless problems with him not listening to me and not respecting my feelings, he did something awful. So yes, the experience of separating before has made me more determined to see it through this time. And it has made me wary of acting on my feelings: I still feel I would like him to come back and take over and I feel like I need him to hold me and make things better... but that isn't the reality of him coming back - he would actually hurt me more. As you said, it would be a short term fix leading to more pain.
My counsellor says people tend to forget pain, and that I am really good at blocking out the bad stuff (not a good thing). I need to remember what he did, the despair of living with him, so I don't go back there again.
The way out of the downward spiral, for me, is to realise it isn't my fault, and to look to the future. To realise that I deserve a lovely future as much as anyone else.
Where do you fancy for the holiday?