Originally Posted by caramelkiwi
Well then, don't you agree that there's no need to be friends with ex-partners? I mean, obviously if you have kids together or something... you have to talk to each other. But they weren't best friends. I've been with him for over a year and I haven't even met her! So they aren't good friends... so I don't understand why its so hard for him to stop being friends with her. And if it was important to him... he wouldn't have agreed to stop seeing her, and he wouldn't have hidden her and lied about her... he would have introduced her. You know what I mean? I've met all his other friends (Guys and Girls!), why not her?
In general, it would depend on the nature of one's significant other and his/her ex's relationship as a whole (meaning nature of any friendship before they "dated"). If it was a deal where I was friends with a girl for a while, then had a "relationship" with and eventually broke it off, if she and I still remained friends, I'd be pretty put off if a future girlfriend of mine requested that I don't talk to her anymore.
Now, if there was no real initial friendship before two people before they dated, and there was no overt reason for them to remain friends after the breakup, that's a little more understandable, although some people are good at remaining decent friends (but nothing more) with exes (but not me, I have a horrible track record of staying friends with mine).
All that crap being said, your situation in particular does seem a bit suspect, considering he lied to you about hanging out with another girl who happens to be his ex.