Not sure about advice but as I see no one else has posted anything yet - here's my thoughts. She sounds slightly confused herself I.e. confused by her sexual preference and not being faithful with her ex - so maybe that's why she's confusing to you.

I wonder whether you're getting a bit too hooked on one girl - i.e. getting to involved and letting it play on your mind. I know we all do it but sometimes it's good to take a step back and look at all the other fish swimming around. Sometimes I just have to accept that some people are confusing (they even confuse themselves) - it's not always down to something you've done it can be more with what's going on in their head, and just not worry about it to much and do your own thing.

Just my 2p