Am I Straight?

Okay so... I'm not even sure if I'm actually Bi or just... curious so maybe some of you can help me out.

I'm posting anonymously because I feel like when this happened I cheated on my boyfriend (who's now my husband)

2 years ago I was drunk and at the bar. I was really close to my boyfriend's sister (who is now my sister in law) I remember talking to her about what kind of porn we like. When I told her I liked girl on girl, she said she did too but she's not gay. Well, long story short the night I was drunk I texted her telling her how I wanted to mess around with her and that I thought she was hot (and she is...) I was surprised that she responded that she wanted to too. So a month or so later, when my boyfriend was working, we were watching a movie after a night of drinking and started to kiss. Then, I pulled down her dress and started to kiss her boobs. We went to the bed and we went down on each other/scissored a little bit. I came literally as soon as she put her mouth on me. It was AMAZING. I literally dream about doing it again but she won't and I know I shouldn't because I'm married now and to her brother! I never got a chance to explore my sexuality so it's a little frustrating. I really want to do it with another girl but I really don't know how I could. Oh and sometimes I can't cum when my husband and I are having sex bu If i think about his sister and I having sex, I can cum almost immediately. Am I bisexual or just curious?