Hoping it's not too late

[MrBond]

"As for the sex, he says that any intimacy he had with OW stopped when we started fooling around. I believe him. "

Then he's not being fair to his GF. He's cheating on her.

"I hope that he doesn't see me having sex with him as me being loose or cheap, because it's been amazing."

It's called Hysterical Bonding. You're feeling the rush because it's not right and he feels the thrill of cheating on his GF.

What does he consider you? I mean you are his W but he has a GF. I know you treated him like crap before, but he's going to have to make a decision or else he's just being a d@ck to his GF.