We all have sensitivities where ever we have sensitivities. We don't get to decide. There's no such thing as over sensitive. You are as sensitive as you are. It's part of what defines you. Your sensitivities won't be the same as anybody else's, just like your preferences for foods or types of music or films or art or books or sports. Sensitivities are simply preferences and dislikes regarding people's behaviour towards you. You have as much right to be sensitive towards x or y behaviour as you do to like or dislike football or romantic comedies. Nobody can tell you you're wrong.
There will be people more sensitive than you, and people less sensitive than you. There are no legal parameters.
If somebody loves you, they will respect your sensitivities, whether they make any sense or not. For example, imagine if you were sensitive to spiders, and didn't like to be near them. If you're in the uk, that makes no sense whatsoever. There are no spiders here that can do you any harm. But somebody who loves you will quietly take a spider out of the house without mentioning it, so as not to upset you. Somebody who doesn't care about you will jump up and down and point and shout 'SPIDER! There's a spider right next to you!! HAHA!', because they know it'll upset you.
So, if you're making it clear that he's hurting you, and he keeps doing it, it's not your sensitivity that's at fault; it's his behaviour with regard to your sensitivity.
If you're not making it clear, make it clear! You don't have to 'fight to be you'. Just calmly say how you feel. 'I disagree, and that comment hurt me.' 'I have a different opinion to you. My opinion is just as valid as yours.' 'It's up to you if you think I'm selfish. You're entitled to your opinion. I don't have to agree with you.' Anything based on the fact that his opinion affects neither your opinion, nor your respect for your own opinion.
Don't have conversations or ask questions. Just quietly state how you feel. Then when he goes all lovey dovey, you can tell him it doesn't feel very loving when he does things like 'that comment this morning', or whenever.
Just get it all said. Get it out of your head and into the relationship. It's not yours to carry. He's currently just doling out crap, and you carry it round with you. He'll never change that, so you must.