I did because I woke up fully clothed with my ex next to me at my mums house. My ex and can be a bit stupid.
I have no idea what circumstances led you to end up sleeping in the same place/on the sane bed as your ex (take it his partner was not attending?) and that is somewhat inappropriate, but at the end of the day you didn't cheat on him with your ex, right?
So he can either accept hat you got drunk and silly at a house party (?( and slept in the same bed as you ex but did not do anything sexual/romantic or he can't.
He appears he can't accept it, mainly because he can't believe you didn't cheat in him. You've told him you didn't, he doesn't believe you, had ended the relationship, and in your last meetup ended up repeatedly calling you a whore and getting physical (??)
Some people would be able to accept it and trust their partner, he clearly cannot/doesn't want to. He sounds generally quite jealous and paranoid even before that happened.
So it's just not going to work for you to continue being wrapped up with him. You should stop contact and figure out another way to complete your project, as many posters have said.
Aside from all this, he seems to see you as a meal ticket, and like you owe him a living/money .. you don't.
He decided you're finished, let him take the financial consequences of that instead of trying to dump you, call you names like whore .. but continue to live off you, be paid by you, stay in your property etc.