Sadly I have to agree. Lets just say I have seen this played out many many times as a frequent ex-visitor to these places.
You are a source of cash for her. She may like you but her world is a mess as BK stated. You are the odd man out...they are co-dependent and will turn on you with a united front if they feel threatened.
This emotional roller coaster will continue if you keep contact with her or him. Best to cut ties...hate to say it...but there are less emotionally damaged goods out there that will appreciate you for who you are.
I still feel like crap. She said that she trusted me and that I broke her trust and that I betrayed her. For the past two weeks, I have been thinking about pretty much nothing but this. I mean, this wouldn't have happened if she didn't go back to the guy. I was sure that it was over for good, because she kicked him out after she found out that he offered to have someone else's child, and that he was either cheating on her or some other women again (A bunch of women sent him naked photos.). She said that he was a lying, cheating -----! I was just trying to do the right thing (Also, there is a BRO CODE!). But I really did screw her over. She told me some very private and personal stuff about her. I still cared for her and, at the end, even though I helped her out A LOT and did a lot of good stuff for her, I hurt her deeply! She has a "Trust No One" tattoo on her, so she doesn't trust a lot of people. She said that I was different. Also, I am jealous of the boyfriend. He is a lucky guy!