I completely understand! Been in your shoes.
Him being more rough or dominant should never be causing you a lot of pain. Unfortunately to get to the stage of very rough and hard sex, you need A LOT of stimulation to get to a point of complete arousal. Patience is key. There are other ways he can assert his dominance over you, and you need to list the ways he is allowed to do so.
I recommend doing the BDSM test/quiz. I did it years ago and it went into great detail of figuring out what kind of things you're into. Things like, do you enjoy bondage, humiliation, denial, pain, edging, pet/feet/oral/whatever play, roleplay, punishments, slave/master dynamics etc. literally everything and to what degree. Comparing these results with your partner can lead to ideas of how he can feel like he's dominating you and you would be a lot more into it because it's probably something you would enjoy too, but haven't tried yet! He could for example tie you up, or have you over his knee while he spanks you. Or blindfold you and play with your body, teasing with a feather, pinching your nipples or having an ice cube melt over your hot body. Getting you to a point that you're begging for him because you can barely hold it in. Once he enters you, he could try doing it painstakingly slow, and then when he can't hold it together anymore himself, he'll let loose and do whatever he wants with you. It's just an example of the type of things that can be a bit more sensual but still in a D/s dynamic