I too am speaking from experience. I have come across a few woman who said they enjoyed being a sub, but instead of just using them to get my rocks off I instead dug into the why. In every circumstance it stemmed from a troubled past. A couple sought the help they needed another ended up commiting suicide after falling into the hands of a so called dom. Sorry but excuses about "trust" and "contracts" dont fly with me on this issue.
I'm a sub yet i've had no traumatic events, never been assaulted never been abused and had a more than happy childhood. No daddy issues, no mummy issues, my twin is my best friend and i'm close with all my other siblings.
I've been with my girlfriend for a number of years now and trust her completely. She's never once made me do anything I wasn't comfortable with and in all the time we've been together i've only had to use our safeword once when we got carried away and went longer than we should with me being tied quite tight. I lost feeling in my foot and we had to stop or i'd risk losing my foot. Being tied up is fun at times but also quite dangerous which is why a lot of trust is involved.
For example there is a game on here called California Bound where a girl spends several hours bound on her knees in a toilet. Her knees would be fucked, within a few days she'd struggle to work and that's if she made it out with all her limbs. People have lost hands, feet even whole limbs from being tied to long and cutting off circulation.
It's not something i'd thought about before I met her but it's a role we fell into not long after getting together. She's quite a bit older than me with a well toned body and the attitude that goes with that life experience and knowing she's a badass. Whereas i'm how you would say "petite". I'm quite small with not much to me, my twin got all the body including the boobs.
I run a quite a busy kitchen so i'm not a submissive in all walks of life, in that kitchen I am the goddess and my word is fucking law. At home I just want to let loose and not worry about anything and my other half fell into role quite easily.
Started off with her letting me know what she wanted me to do in bed to handcuffs, blindfolds and eventually full on tying up. We don't go beyond light stuff, despite being her sub i'm not into pain, i'm a bit of a wimp.
She likes to be in control and I like her being in control, it makes the tenderness at the end so much better.
What you describe isn't a dom/sub relationship it's the SM in BDSM. That's where the extreme stuff lies and the pain and the cruelty.