Maybe hormones, I think I read that on the sexual health forum. I'm not really sure tho, mama.
I am bi too and I go through spurts where I want am attracted to females more than males vice versa might be hormones due to pregnacy might not be cause I go through theses moments all the time I have always just dated a guy or just dated a girl never both at the same time and they have all been what I felt thought was a serious relationships and ended cause they ended it or over a very legit reason like them cheating etc.
But then again I am one to put my all In a relationship and do what it takes to make it work unless its just not worth trying to do so.
Im pretty sure its the hormones. These darn hormones have been makin me feel all kind of ways. Lol. Have you told your bf