Ask a Bougie Chick - Does a zebra ever really change his stripes?

Wrapping up the week, a letter from Dee who has this one ex... should he also become the next? Take a look...
I was dating a guy, CJ (not his real name) for ~3.5 yrs. We had our ups & downs. My fault was thinking I could force him to want a different type of relationship (focused on heading towards marriage). His fault was an emotional obliviousness & insensitivity common among men in their early 20s (I'm nearly 6 years older than him). We had two periods of not being together (6wks, 3mo), but outside of these breaks we were in an exclusive relationship. There has never been any evidence of cheating & no drama caused by outside parties. 
Less than a month ago, I decided that we needed to terminate our relationship. We argued a lot, his inconsiderate behavior was reappearing, and he started to exhibit problematic behavior (calling more frequently when he knew I was out, throwing a tantrum when I went on girls trips, trolling FB & blowing up over innocuous posts by HS classmates - nobody I dated, fwiw). 
Now, he was always a little emotionally daft in regardless to showing me that I was/am a priority, but his controlling nonsense kicked up last yr, when our relationship became long distance. But, after another incident of his ridiculous jealousy I realized that I needed to get out before things escalated.  I said we needed some time apart, he protested but eventually agreed. We don't FaceTime or talk on the phone, but we occasionally tweet & email. I would have cut off all contact except we are in the process of negotiating some stuff regarding joint intellectual property, and our breakup was civil so I harbor no hard feelings. 
He has always said that he wants to become a better man & try to rekindle our relationship sometime in the future. I do love him, but I'm not so wrapped up in my feelings that his resolutions move me. I'm not opposed to starting over after some time has gone by (at least 6mo); however, I don't know how I can judge if he's truly changed outside of the confines of a dating relationship? What do I need to look for? And, how do I do that since I've drawn very clear boundaries, and am no longer interacting with his friends & family (&vice versa)? 
I'm not too worried about what happens between us since I'm focusing on some goals I'd neglected during our relationship & using this time to rediscover me (& get comfortable w/ being solo again). I guess old feelings, and a feeling that at least hearing him out is the fair thing to do, are the only reasons why I'm even entertaining a future with him. 
I appreciate your insights, and the opinion of the Bougie faithful.

My first thought is: what has he really done to rectify his past behavior? He wants to become a better man but is he doing anything visible or tangible to achieve that goal? And since I am Queen of the "Oh let me give him another chance because I love him so" let me offer this advice - give yourself some time and a clean break and see what life is like without any part of his world touching any part of yours. If it feels pretty good, there's your answer. 

Bougie Faithful instead of lobbing your idea a la machine gun fire, why don't we do this differently? Pretend that you are Dee or that Dee is your sister... what do you do or advise her to do? How do you know if dude has really changed or changed for right now? Does a zebra ever change his stripes? Leopard change his spots? You know what I mean...