I don't know whether you could call it "unfaithful", but at her age, it's kind of ragged behavior to have sex with some guy a week after having sex with you.
Not very dignified or respectable.
If you want to have an exclusive relationship with this woman but maintain separate households for several years (maybe the best thing since the teenagers can't seem to get along) that might be a good goal. But I think it would take a real "Come to Jesus" meeting with her to make that happen. Really, she's too old to be acting this way and then to TELL you about it - really doesn't sound like a good bet for a stable long term relationship.
It can't be called cheating unless you guys are together..you can still feel betrayed because you never got the closure you needed, but now that you have a chance to be with her again maybe it was a way for her to see if she could be with another man other then yourself or if it was you she really wanted. You never know, maybe thats why she wanted you. I know that when I was seperated from my fiance I was dating another guy and slept with him. After a while i got back with my fiance and told him about it. He called it cheating as well but I told him that it just made me realize how much I would rather it be him. And that I didn't want anyone else. He accepted that and hasn't brought it up since. He knows he can't call it cheating, but felt hurt from it and it made me feel bad, but we moved on and were happy together now.
If you love her Marry her and stop the chaos, after all you 2 are the parents, and they are the children, and set some boundries for the teens, and yes it was ok for her to go with the other guy you were not together Either love her or leave her alone. luck jo
I don't think there's anything for you to forgive since you two were no longer seeing each other when this happened (if I'm understanding this right). She didn't cheat on you or betray you or anything like that. You two were no longer dating, during that time in which her life is hers to live. She realized that she wasn't over you and wants to give this relationship another chance. Do you feel the same way?
Only you can decide if you want to make it work with this woman based on YOU and HER. If you want to be with her, then be with her. But if you don't want to commit to making this relationship work, then it's not reasonable to expect another person to be faithful to you when you're not in a relationship. I think if you do want to try again, set some new ground rules. Don't just have a bad fight and not speak to each other for two weeks. If you disagree, agree to try talk again the next day when you two are both calmer. Don't leave it an open door for a situation where it's not clear whether you're on a break, you've broken up, or you're just cooling off.