Wife left don't know what to do?

My wife left about 2 weeks ago and says she is ordering divorce papers online next week. Started off the week before she left I seen something on her facebook page saying she was wanting a specific person to text her. I seen it and asked her about it. She said it was nothing just someone from work she was wanting to ask them something because they left early that day. I didn't believe it. She said she had no desire to leave at all. Two days later I text her at lunch like normal and she got mad about it. So when she came home I asked her about it. She said she needed a little space but didn't want to separate or divorce. So in the afternoons I started trying to do my own thing and give her a little space. 4 days after that she comes home and says she talked to her brother and is going to live with him and is thinking divorce but claims there is no one else. So she leaves that night. She is texting me that night saying I'm her best friend and that she will always love me but this is about her needing to find out if she can stand on her own two feet. Me and her brother are good friends and we hang out a lot even before me and my wife started dating. We were friends for about 6 months first been married for 31/2 years been together for 6. So she comes by about 4 days after that and says she wants a divorce. I told her okay but I think her reasons are bs. In between then and today when she comes over she kisses and hugs me and flirts with me alot. She calls me up yesterday to say she's ordering the divorce papers next week and then she says things that hints at another guy from work and when I call her out on it she starts getting mad and trying to change her story. Then she goes into saying I care about you but I'm not in love with you anymore and then says she's not attracted to me anymore. She goes to her brother and talks crap on me to him and he of course tells me what she has been saying to him about me. He thinks all her reasons for divorce are bs also. I still love my wife and want things to work out but I think it's one sided. I know she is bi polar and won't take her medication. She has even said she thinks she will regret divorcing me at some point. I was thinking about just cutting communication with her for a little bit and let her come to me. Her brother is the only friend I have and it's a little awkward to go see him if she's there but she's usually stays out all night about once or twice a week supposedly staying at one of her female friend's house. I don't believe that either. I don't really know what to do or how to move forward here. I've been exercising a lot and going out to see movies but that's really about it. I don't know what to do here.