"sex with ex, huh? Always food for debate! :-) At the risk of sounding unrealistic and inviting public wrath, here are my two cents' worth-- if the girl (or guy for that matter) has sex with the ex while being, as harman put it "pretty devoted" to you, that's a cry for help. what kind of help, you might wonder. well, help regarding your sex life with him/her. for your partner to seek sexual gratification elsewhere (ex or no ex) is a sure sign that you're not doing the right thing or enough for him/her. now i can't tell you exactly what might be going wrong -- only the two of you know (or at least one of you does, which is why this is happening in the first place). so even before the question of forgiveness raised its head, you have your task cut out for you -- gotta find out why your sweetie pie wanted to be baked in someone else's oven. hey, if this sounds unreasonable to you, forgiving your partner would buy you a one way ticket to fool's paradise! " SimpleGal with Great opinions .... !!! impressed !