Whether you tell your boy friend or next, please do tell your ex to piss off.
He sounds like a very horrible man and you are much better off without him.
Plus I think take a long hard look at your judgments and boundaries. Why the drinking with the ex? You say you had a lot to drink but you managed to make sure the sex was safe. So you were aware of what you were doing. I am not being mean, your life, your business but I am just saying what were you thinking?
Maybe this does explain it a bit...
"He was very abusive towards me when we were together. Lots of coercive control, violence, gas lighting etc. But I know that’s no excuse for my actions, because he didn’t make me have sex with him, yes my barriers were down due to intoxication but he didn’t make me drink either. I own my own actions."
Maybe having being used to his vile behviour there was some something going on there for you psychologically. Please do not beat yourself up about this.
Are you sure you are ready to move in with your new man when the old one can exert such power over you?
Please contact Women's Aid and do the Freedom Programme. I think you need some help to work out your boundaries etc and I really do mean that in the best possible way.
I hope it all works out and you.