Breakup Dilemma w/ Son's Father! Please Help!!

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I'll try to make this as short as possible. I'm open to any & all advice & suggestions!!
So, after having a child (who will be 3 in November) from a "friends w/ benefits"-type relationship, about 2.5 years together & living together for 9 months, I left him & my son & I moved back to my hometown exactly 2 weeks ago. It's too long of a story to explain all of the reasons, but it was the best decision for both myself & my son. My son's father was only with me b/c he felt it was "the right thing to do" & he made it very obvious! We moved out-of-state with him, leaving all family/friends & work behind, b/c he had a great job opportunity. Although things were never great & I still never felt like his "girlfriend" for even one day of the entire 2.5 years, he promised it would be different after we moved with him.. So we did & obviously things didn't get better. We were arguing daily & didn't speak otherwise. I was so unhappy & it was affecting our son.
Anyway, this is my question... My birthday was Wednesday & I literally don't ever get out of the house & haven't many times since our son was born. I'm on my way to TN right now, where my son's dad is. I need to get the rest of our stuff anyway, but my son's dad wants me to "give him one more chance" & to finally hang out with just the 2 of us -- which literally hasn't happened since the day I conceived our son! I begged him our entire "relationship" to just spend a few hours together outside of the house & it never happened. He owns a bar/music venue & one of my favorite bands (& another band who one become good friends with) is playing there tonight. He had to get permission from the band & their management to change the name of the event to include it being my birthday celebration. I'll be there for sound check & to hang out beforehand. This is very nice of him to do, but we have so many unresolved issues & I'm not sure how I can just ignore that & try to have a good time with him. He took off work tonight too, which he has NEVER done! I obviously don't want to have a serious talk with him while we're out at a packed/sold-out show, but I don't want him to think everything is okay if we do end up getting along & having a good time. It's too late to change my mind & not go. Should I just see how things go tonight & be open to giving him "one more chance" & just talk to him tomorrow before I start packing the rest of our stuff? Or should I just consider this a nice gesture & (hopefully) good beginning to a civil coparenting relationship, then just continue with my plan & start packing when I wake up tomorrow, regardless of how tonight goes? 
There's so much to this & I know this probably sounds very petty, but I don't ever want to have any regrets with my son not having both parents around! Thank you for any advice!