I totally agree, Lilibet. It's easy to assume that RP was the dominant figure in his relationship with BD. But, I have wondered if BD was domineering and manipulative in her relationship with RP. As OceanBlue astutely pointed out, men are sometimes abused physically and/or emotionally by women. We don't know the actual situation between RP and BD, but it's possible that BD domineered RP. I do think BD had her eye on RP's income as a doctor and was pushing him toward marriage to get her hands on his money. RP may have been reluctant to marry her but didn't want to hurt her feelings and wanted to help her get on her feet.
One thing I wondered when I read about BD announcing to people that she moved in with RP is whether she took it upon herself to do so without RP's approval, which does happen. Just speculating, but it is possible that BD was shrewdly making demands and perhaps RP is an unassertive, compassionate man whom BD could easily manipulate. I am inclined to believe that because of his mother's comment about BD needing to see a psychiatrist.
Manipulative people can easily make a person feel guilty and they are very subtle about it, even passive aggressive sometimes. They like to test the waters, so to speak, to find out who is susceptible to their coercion. I had a friend who is like that. She claimed she was abused by her husband. She swindled me, and I'm sure others, out of a lot of money. She makes people feel sorry for her, claiming she is sick, disabled, broke, abused, mistreated, etc. When she lost her home (because of greed, really), she asked to stay with me and I acquiesced with the understanding she was going to get a job and then get an apartment. Immediately, she began claiming for herself things that were mine, even a chair that has extra padding because I have a back injury, and my cane. She always had an excuse for not looking for a job. I realized she didn't plan on leaving but didn't want to add her to my lease because I knew she'd take everything I have, so I insisted that she leave and gave her a deadline. Some of my things she wanted to take with her and I did let her have a few things but had to put my foot down again (I interpreted her attitude as "Because you're making me leave, you owe me"). I realized she had lied to me (and others) to con us, and I began to suspect she was the abuser in her relationship with her husband, at least emotionally. She has a narcissistic personality and tries to convince people they should simply do as she says because she is superior. People like that take advantage of people who are easily manipulated but when the other person stands up to them, they play the role of a victim to garner sympathy from others, including their victim.
ETA: Another thing regarding my "friend," which I pointed out to her after she moved out and was still making demands of me and blaming me for her situation, is that people to her are only tools that she uses to get what she wants. Several things happened that demonstrated that she really doesn't recognize the needs, limitations or even existence of others. Everything centered around her. I easily see BD that way. To her, KH was just an obstacle to what she wanted. I don't think BD even saw KH as a human being because she is incapable of empathizing with others.