Reading your post reminds me how much I wish I could be a lesbian too!
Men don't just want to have sex with their ex's--they want to have sex with ALL women! Ex's are just easier prey because of their vulnerability!
When I left my first husband, not only did HE keep propositioning me, but EVERY SINGLE ONE of HIS friends propositioned me as well! After all, having left him after discovering that his GIRLFRIEND was living in my attic made me ESPECIALLY juicy prey, because they perceived that I was exceptionally vulnerable--you know, like tigers go after baby does and the deer who are already crippled.
That, and the fact they thought with the circumstances surrounding our break-up, out of REVENGE, I'd be a WILD WOMAN in bed with them. My EX even tried to get me to have sex with him, telling me that by doing so, I'd be able to get "revenge" on his GIRLFRIEND for breaking up our marriage!
But I have more self-respect, and besides, I'm really GOOD at getting revenge without having to resort to lowering myself sexually... (Oh, for anyone who read my initial post....I'm not a WHORE!)
Your ex-boyfriend may also think that you will SCREW him to get back at his current girlfriend--lots of women do! I know my current husband's EX keeps coming on to him--hoping to get him to "give in" and screw her--and thus, hurt ME to the point of breaking up with him so SHE could get him back...(of course, she'd just DUMP him again...but it's an EGO thing for her).
It's not just MEN who do that! Plenty of sick demented women do it too--but NONE who you should want to be involved in a relationship with!
Another news flash for you...he is LYING to you about his girlfriend "doing everything he wants sexually"--if she did, he wouldn't be coming on to YOU! And he's also LYING if he says he LOVES her, and he didn't love you either, or anyone else either, because he can't because he doesn't love himself.
Don't you know? In order to be able to love another human being, you first have to love yourself, and you can't do that if deep down you know you're a SLIMEBALL because you treat the very person you are supposed to care about the most like SCUM! He can lie to you and everyone else, but deep down he knows he's nothing but a SKANKY HO!
OH, and if he's telling you all about his sexual relationship with HER, you'd better believe that he's already shared all the NASTIEST, most INTIMATE details of YOUR sex life with HER! Gentlemen don't talk--and the men who do--talk to EVERYONE--and that means all his friends know too! "From what he tells me he can get her to do it if he was more insistant?" Why the HELL is he telling YOU that? Oh...it's because he's already told HER that he got YOU to do it! Do you appreciate his NEW woman knowing that? Don't even THINK about deluding yourself into believing him if he's told you that he doesn't talk about you to her--you already know he's a liar!
What's not healthy is for you to be talking to him at all! Disfellowship the asshole from your life. Oh, and I personally think you'd feel better about yourself if you paid your own gym membership. I personally would also just pay him back the money I owed him, even if I had to take out a bank loan to do it--my self-esteem would be worth the bank's interest!