Have you ever dated someone who thought they were gay or les but break up w/ u cause they are str8?

Okay, so I’m a girl and when I was in middle school I dated this girl that I liked and she liked me and confessed to me. We dated for four months, we went on dates, held hand, and kissed a couple of times. Her mom even found out and didn’t like it but that didn’t stop us from loving each other! After 2 months... things started going a little down hill, and she kinda stopped talking to me as much as she used to, and talked to my other guy friend more. I thought she was cheating but I pushed that thought aside because I loved her and thought “She wouldn’t do that to me:)” but I never found out if she did. 2 months later Valentines is coming up, and... she dumps me. The way she did it kinda hurt because it was like in a playful manner.. Her “I” Me:”You” Her: “Want” Me:”You Want” Her:”To” Me:”You Want Too...” Her:”Break” Me: “No.” I was laughing because I thought it was a joke but then she said, “I dont think I’m pansexual... I think im straight.” So I was upset and I was just done for but I never cried over it and I never asked her if she cheated on me. My friend, me, and her are still friends (●￣(ｴ)￣●) Should I ask her if she cheated? If so how?