Not mentioning this to B wouldn't make me physically unsafe, but I do plan on talking to him at the end of the week even if something comes up or he says he is too stressed to hear it.
I would not let myself be anyone's 'punching bag'. I think if he showed enough remorse I would give him another chance, with a very clear 'any attempt to cause me harm in any sense and it's over' clause. I won't immediately trust him again and I certainly don't think 'I was drunk' is a good excuse for anything. However he's not looking like he's going to show remorse so it's not going to happen that way.
Went to the link and I believe anyone can tick those boxes sometimes; male or female. There aren't any significant issues highlighted by the list for B, though I worry that A has blackmail type material on B and B has said he feels like he couldn't offend A without fearing it gets used. Not a healthy relationship :/ I also believe A doesn't really love B but has used him to get what he wants (e.g. alcohol bought for him when he was under 18 and lifts about town)- a little psychopathic I always thought, along with lack of remorse.
The best scenario would be for their relationship with each other to naturally fall apart without me, as I guess I was hoping for. I want him to make the decision not to be with A on his own, either from respect for me or self preservation for himself. I feel very much alone
I don't want to lose B, I've never been in love with anyone in the same way so really want to make it work with him. The problem is, B still feels the same way about A.