We all make decisions that in time we regret, he seems to truely care for this girl and she's taking that to her advantage. Have you ever cared for someone and allowed flaw's to subside because of it? I know I have, with family and friends. She knows the course of her actions and is playing in her field. She knows he loves her and if she googles up to him the storm cloud blows over and all is well until the NEXT episode of drama. I (and if you read correctly) said I don't know her and she may be a wonderful woman... but he's allowed her to do this to him over and over again and its not healthy... therfore he needs to bail. BE DONE with all this bullshit.
If you know B, and have talked to him then you will know that he's a very giving person, she apparently also knows this and is taking it to her full advantage. Its sad what we will do and take from those we love, but sometimes that is life.
It can be looked at two ways... what is the difference between this and a woman whom is beat up often by her bf, and doesn't leave because 'he loves her?' emotional and physical abuse are on the same playing field IMO. Its not only women whom endure these speed bumps, men do too. Its hard to let love go and move on, and seems B has love for this girl, and wants to make something that isn't there. She's taking advantage of his sympathy and his kindheart. Thats all I'm saying, she knows what she's doing and I'll be damned if I will say he's wrong in this situation. She is an adult, as is he. He needs to just walk away, she's no damn fool... She's no virgin to this drama either.