Going out to bars while in a relationship

Please no hate! Hey guys, I need a little advice. Long story short me and my boyfriend broke up about a month ago and started talking again and decided in a few months after working through our issues we would officially start dating again. Problem is my sister hates him. And I live with my sister. She bad talks him constantly. She knows we are talking again but is convinced on "helping me move on". I don't want to move on I love this man with my whole heart. We are keeping in DL because of drama. Anyways my sister and some friends are going to the bar friday. She keeps trying to convince me to flirt with guys for free drinks. I feel guilty thinking about it... I just want to go to the bar and have fun with NO boys. I guess I'm just asking for some advice? Or maybe encouraging words? I'm just lost. I want to be with Guy but I also wants a relationship with my sister and to have fun in college..