<human>: Can you provide a brief rundown of the text in within 3 sentences?

I'm starting to really like a friend of mine, but she's in a pretty long term relationship.  It's kind of shaky at times (the relationship with her SO), and I've always had the sense that it's going to end.  I would NEVER get in between a relationship, no matter how bad it may seem (you only hear one side of the story), so that's not really my issue.  Every time I hang out with her, I feel kind of scummy because we are obviously flirting.  My question is, should I move forward with our friendship, or should I cut ties?  I really don't want to cut ties, but I also don't want to cause a rift in a relationship.  Also, I've never actually met her boyfriend, but I'm not sure if that would make me feel any better.
<bot>: Starting to have pretty strong feelings for a female friend of mine who has a boyfriend.  Not the kind of person to get in the way of a relationship, but wondering if I should keep up the friendship for her sake.