I'd be more worried if it is you that is being used right now.
Considering this is a first kinky relationship for both of you, I have to wonder if you are active in your local community. Getting to meet others in the scene, especially other sub women, might be a really good idea. From what I understand, it is very common for subs to get very attached to their first dom, and maybe gloss over the parts of the relationship that are not that great.
Has your self-image in general improved, and does it keep improving, once you started out with him?
Me: bi female in my twenties