I feel like this situation is very similar to my own. I did make a LONG post about it, but I fear I was mostly rambling. I might have to come back at some point when I've had sleep and food and re-write the whole thing.
The biggest difference is that my fiancee and our mutual online friend have not taken anything physical. She's come to me to discuss this before it gets that far. Granted, it feels out of control.
I've never been very good at taking care of #1 and this is hitting me hard as well. But having seen that these things can and do work out, this gives me hope.
Closetpoly has some great advice that applies to my situation, thanks for that.