What’s your opinion on women that talk to multiple guys at once?

I have this girl friend, we’re not dating officially, we’re more like friends with benefits. We kiss, hug and she tells me that she likes me but we’re not dating (weird huh?). Anyways, there’s this guy she talks to. I asked her if she had something going on with this other guy and she’s says no, although she did admit they have gone on dates before. She told me that the guy has feeling for her and actually asked her to be his gf. She told me that he’s a really good guy and all but she also told me the reason why she wouldn’t date him. Like 20 minutes after she told me this she started to kiss me and told me she liked me. I want to believe her but I feel like there’s something she’s not telling me. I’m sure she’s kissed the other guy too (although she says no) but I have no place to tell her to stop because she’s not my gf (only friends with benefits). We were on a formal relationship once but we broke up because I had problems expressing myself to her. I mean, we still kiss and all but it’s not a formal relationship. I don’t know if I should stop talking to her (although it will break my heart because I love her) or become less attached to her and maybe talk to other women or make her choose between me and the other guy or just treat her like a friend with benefits. What your opinion on this?