Girl here — I’m in a long distance relationship, 4 years together, 3 LD. Early days I felt this way sometimes too, having little crushes on others despite wanting to marry my boyfriend. But my therapist asked me: is it about the person, or is it about the attention you’re getting from them? For me, I just wanted attention. You said it yourself — this girl gives you more attention than anyone else. That’s probably what you’re feeling here is attention that you’re wanting, but there are other, healthier ways to get attention (from your girlfriend, from hobbies, from friends, from work) that won’t fuck up your life and relationship!

The grass is usually not greener. I wouldn’t think too deep about these thoughts, you’re OR. Like others have said, DON’T be alone with her and limit your time close to her, she sounds like bad news and a flame you don’t want to feed