When reading your posts, one thing which came to my mind is that the female roommate may feel insecure and threatened by the presence of another female in the living situation, as she tries to establish this relationship with the man. Still unfair to you, needing a place to live, but she might feel very insecure and threatened by your presence.
Also, if this is the case, rather than kicking you out, she and he should look for another place, since this is none of your doing, and you have stated that finding housing is difficult in your location (where are you?).
In my own personal mindset, I'd feel whipped and just start looking for another place to live...having let people run over me like that most of my life ! Also, not wanting to try to live in an adversarial situation where I clearly wasn't wanted. Too bad your roommate doesn't feel safe living with three.
Patty