TL, DR: Woman identifies herself as a 'sex slave' because her husband used coercion, emotional and sexual abuse to force her to do things she didn't want to do, even though she didn't realize at the time that she was being abused. link:https://archive.is/klDRZ

I'm posting this because it's often discussed on TRP how definitions are often broadened to fit certain group's agenda (such as broadening definitions of rape, sexual assault, etc.).
There is an AMA in the 2X subreddit where a woman describes her ordeal as a homegrown sex slave.

Now I definitely think what this woman went through was horrible and her husband is a creep, I wouldn't describe her as a 'sex slave'. Although in her title she mentions sexual abuse, she never indicates that her husband used any physical force on her, but since she considers herself a 'sex slave', her definition of rape may be different too. She only describes him using psychological abuse to get her to do what he wanted or to get her to regret not following his bidding.

The abuse actually started long before we got married. We had grown up together, but while we were dating he was in the Army. The crazy thing is that most of our dating relationship was long distance, and yet he still held a crazy amount of power over me. He was a master manipulator. One minute he would be writing me poems and telling me how lucky we were to be together. The next he would be asking me to do gross sexual acts over Skype for him. If I was hesitant or refused, he would bring up all the good things he'd ever done for me and accuse me of being selfish or not loving him. A month before we got married, I flew out to where he was stationed (he was in the Army). That night he actually raped me the first time. That's the biggest red flag that could possibly exist, but we still got married a month later. Looking back I'm humiliated by my actions, but at the time I genuinely believed that I was wrong for not enjoying what he was doing to me.

Fortunately, eventually a group of her comrades can see what her husband has somehow blinded or brainwashed her from seeing:

The man who was my husband and captor at the time was in the military. He deployed and although that lessened his control over me, it certainly didn't eliminate it. We would Skype every day
(his job didn't require much field work) and so the emotional choke hold he controlled me with was still present on a daily basis. While he was deployed, I decided to enlist as well. While in basic, I met a group of AMAZING women. I wasn't willing to admit I was being raped or abused, but I did open up to them about some of my problems in a round about way. They put two and >two together and pushed me to leave him. At one point they literally walked me up to our Drill Sergeant and said very matter of factly that I needed phone access so I could get a divorce. The DS was pretty stunned but agreed to let me have my phone. They then took me to an empty part of the barracks and watched me while I called and told my husband that I was through. If it wasn't for the distance and safety that the Army offered along with the strength and love of my friends, I honestly don't know if I ever would have gotten out.

She describes an incident in which her husband hosted a sex party where he performed oral sex on her, even though she really didn't consent to it due to the coercion and emotional abuse. In her mind, he should go to jail for being her 'captor':

He's not in jail. He wasn't even taken to court. I went every avenue I possibly could to bring him to justice but I was dismissed every time. I contacted CID (military investigators) first since we had both in the military previously. They decided not to pursue since he was not longer enlisted and encouraged me to call the local police of the cities in which he raped me. None of them wanted to help since we no longer lived there so I called CID again. They literally refereed me to three different FBI offices who all turned me away. Finally, I found an investigator in the town we had both grown up in to look into it for me. I provided plenty of witnesses and kept in contact with all of them, but only one witness was ever called. The case was eventually dropped. I don't think he was ever even interrogated. As far as the people who were participants in what was happening, they didn't realize what was really going on. My ex-husband presented each situation as consensual, saying that we were swingers or that I enjoyed it, etc etc. I asked them to be witnesses on my behalf, promising that they would have full immunity. None of them did. Each one replied with his or her own version of "well if you didn't like it, why didn't you fight harder?"

My question is this - with the exception of possible physical rape (which the OP never mentions, so I'm assuming there was no force - but there could have been) what crime did he commit? This guy is certainly an extreme manipulator, but if pressuring your spouse to experiment with something kinky they normally wouldn't do makes someone a 'captor', there's probably a lot of men and women in this country that can also be called 'sex slaves'.