It seems to me like this guy wants you in his wedding primarily because when something inevitably goes sideways, he wants to put the responsibility for unfucking that on you. You really don't owe him that. Also, it is pretty disrespectful to say, effectively, "let's reconcile but we're doing it on my timeframe so you can do a bunch of work to make my life easier." Yeah, it sucks that you have to be the one to say no here, but this guy is clearly the asshole for expecting you to do the work of sorting out the issues between you two by fucking July.
It's complicated. I told my wife last night that fundamentally, I could be defined by the fact that no one in my life supported me until I met her. We had an interesting discussion last night about "education" and what it means; I've been doing a lot of self-guided exploration of watch brands and their success and failures (ever seen a luxury brand commit suicide?) and she asked if I was still learning anything. I said that I wasn't really but that learning wasn't the point; she observed that learning doesn't mean you go in with a specific goal and I said "learning is spending enough time to pass the test and anything beyond that you're just an uppity shithead looking to get pounded" and she wondered how a kid whose parents share five college degrees between them would end up with such a perverse understanding of "learning." I observed that Occam's Razor on my childhood is they viewed me as a pain in the ass so I learned not to be underfoot. Anyway. The three months I preferred sleeping in a car to sleeping in my house? His parents put me up. His dad is the one who taught me how to drive. I've known him since 8th grade; I started writing screenplays because he needed one. He's the one who moved out to Hollywood and got the MFA from Art Center; I'm the one who popped down and had a six figure union gig within a week of getting off the plane. He stopped talking to me for a year out of jealousy for that. He knows he's the asshole. But he's always been the asshole. For thirty years, he's been the asshole and I've put up with it. For thirty years, I am the unfucker. His shrink once had him pass along the message that I am his fundamental pillar of mental health. What's changed is I'm not putting up with it at the moment and I'm sure that's got him mightily confused. After all, he started talking to me again when I got married so he was willing to put his differences aside. That he was the one with the problem is immaterial. Really? I'm a steeple-chasing horse staring at an eight foot brick wall. In theory? I might be able to get over it. In practice? Sucker's gonna break all my bones. And the jockey doesn't understand why I won't jump because until now, every time he digs in his heels I go higher.