BDSM dom/sub, m/f, happy ending, female sub USED to self harm on her thighs (accurate but not that important detail) who had a previous dom that looked down on her for it)

[Nia]

I read this book about 5-6 years ago, it was pretty modern and I read it online (illegally) lol. The sub enters a relationship with a man. The plot isn't very exciting from what I remember, just their relationship. Not dark in any way, and there were quite a few BDSM scenes. Not sure if it was part of a series. And I don't think this book was very cheesy, at least compared to other BDSM books.

Here's what I definitely remember:

1. A harsh spanking scene in which the sub is getting punished, she's crying a lot. The dom conforts her after. The spanking I think was in a special chair. (before this spanking there was another one, but not as harsh). The punishment could have included something else besides spanking but I don't remember

2. She used to self harm on her thighs. Her previous dom didn't say anything about the scars, except on one specific incident.

3. There is no club (during the book, maybe at the start it's where they met)

4. Their relationship gets more affectionate as time passes, I think at the start it wasn't very personal (they weren't close from the start)

Here's stuff that could have happened (but I might be confusing with other books):

1. They are in a relationship where he makes a lot of choices for her, like when to exercise and what to eat
2. At the start she's told to let herself in his house at exactly the time specified, otherwise she'd be punished
3. She wants to be "disciplined", but I don't think she was willfully disobedient
4. MIGHT be 24/7 but I don't remember a collar
5. She was probably middle aged