I am falling for my brothers baby mama

So this is gonna be a bit complicated and title sounds worse than it is People involved: Me:26m Fern: 20f My brother(deke): 22m
Background: Fern and Deke dated for about 3 months about two years ago and he accidentally got her pregnant. Deke freaked out and ended it with her bc she didn?t wanna get an abortion. Her family ended up kicking her out when they found out she was pregnant and showed up at my parents house who basically told her to **** off but I was luckily about to leave their house and heard it all. I offered her my guest room and originally it was going to be temporarily but I told her she could stay as long as she needed. Since then we have spent a lot of time together and she gave birth to a healthy baby girl who is now a little over a year old. More recently I?ve been finding myself trying to spend as much time with her as I can. She just makes me happy and little things have been changing like the other night we both were watching a show on the couch and she put her head on my lap and I found myself starring at her. Or a few nights later when she made me lay on her lap so she could play with my hair. She also does small things like packs me a lunch or sometimes makes dinner for us all. Those are just a couple of examples but long story short I think I?m starting to have a crush(?) on her. I constantly find myself thinking about Fern or talking about Fern or spending time with her. I don?t really know how to approach this or if I should at all. It all feels more complicated than it should especially since she?s the mother of my brothers child. I?m really unsure of how to proceed and would love some.
TL:DR: my brothers baby mama moved in with me after getting kicked out and we have grown close and I have a crush on her
Edit: my brother signed over his parental rights and my parents barely speak to me as I chose to take Fern in instead of joining them in shunning her.


Source.