first of all im sure he has other friends and family members that can help him if he's going through something.
once you sleep with someone it's easy to do it again. her talking to him is like stabbing you in your heart. if she's talking to him knowing she slept with him, you dont know if her feelings for him will grow. it's something there for her to do it in the first place.
you can start having female friends and she how she feels. or you can be firm and tell her your not having it.
my ex of 5 years gave women who liked him my phone #, while he was living with me. i nipped this in the bud, but that was one of many red flags for me to dump this guy.
she's telling you how yall relationship will be in the future.
she could care about you but not be serious (want to live the life of a single person).