He's probably watched a lot of porn if he thinks that everyone he meets will be interested in his 'coercive' tendencies. He probably could change, but the question is, does he want to?
You say he accepted it when you told him his behaviour was unacceptable. Did you actually have a frank open discussion about sex and boundaries or was it just a case of "I didn't want you do x" and him saying "OK, I won't then".
If he has been able to talk freely about the things he likes and why he wanted you to join in, while listening to you talk about your desires and comfort levels and what you expect from him, maybe he can change.
If you get on really well and enjoy sex with him then I'd say go for it, but at the first sign of him overstepping you need to be prepared to call it a day.
FWIW I finished with my DP over something (not sexual) which I found unacceptable. We had a miserable month apart, both wishing we hadn't separated, and when he contacted me we had a lot of in depth discussions about what we would both tolerate within our RL as well as couples counselling etc. He absolutely HAS changed so I know that it is possible, but this came from a very deep desire to make our RL work, not just wanting a shag.
I don't know how close you were to each other last year, as you say you were 'seeing a guy' and evidently got straight into sex when you first got back together, so it sounds quite casual. If so, what is drawing you back to him?