I dont know what to do..

Hey guys how you doing? ok so this is my problem i've been dating this girl for 5 years now, and we broke up around 2 or 3 months ago so she went to cali for vacation, with her sister, her brother in law, and her nephew to her long time guy friend she knows this guy since way before me.

The things is that the week she spend over there they kissed a lot, probably, but she says they didn't had no sex. When she came back from California three weeks later, we started dating again so now we back together last week i had her phone because i was calling one of my friends so in the middle of the conversation he text her and i got mad at her because she was still talking with this guy so i asked her to stop talking with him, but she doesn't want to, she says that if she wants to stop talking to him she will but not because i told her but because she wants to.

So i don't know if i was right to confront her about this should i leave it alone? is this bad news for me?? she tells me not to worry about it that she wants me and only me that she don't want him but they been friends for a long time and she doesn't want to end that friendship so what i should do?

Thank you in advance for your advice