She didn’t mean to. It was just a simple friendly dinner with a friend from work when they were out of town closing the sale. But after the third glass of wine his hand was resting on her knee but it was totally harmless, so she just left it there. And yeah, they were snuggled up in the cab back to the hotel. And ok, maybe she did go back to his room with him, but it was just for a quick nightcap. One thing lead to another and… well, look, she’s really sorry , ok?
This doesn’t mean that she doesn’t care about
you. She honestly does. But the fact remains
that she is not the sort of person who can
make and keep a monogamous commitment to
someone, even someone she loves. Maybe you
thought you could change her. Maybe she
honestly thought things would be different this
time. But they weren’t, and now you have a lot
of questions that you need to ask yourself.

How You Can Stop It?

By making her know how wrong it is to be promiscuous.

Leave her. luk for who dont have a pro wit monogamy

If the cheat can't stop it, no other human can do it for him/her.

If she can't and doesn't want to stop cheating, then you can't stop it. Stop complicating your life, move on to another lady that can be faithful. Simple.