Frustration in my relationship

So its happening again, now he is having issue with me growing out my hair into a tied up manbun. The last time it was me dyeing my hair blonde.

This feeling of control over what I can do for myself is really putting a toll on me and I am rethinking of even wanting to be in a relationship. What am I in a relationship for? To support one another to bring out the best and support one another in what we like. Right now, I feel that I have to satisfy what he prefers is right. This is the reason why I do not share information with him transparently all the time.

I told him I will be meeting guys I met from the pool party for dinner and he got somewhat upset about it by bringing up about how he felt during the pool party when those guys were not reciprocating attention to him. However, before I brought up this whole dinner thing, he has repeatedly told me he was fine with it.

Today at the gym as I changed back into my used gym attire, I got reminded again about how he would repeatedly command me to shower and/or wash my hands with soap after the gym, and it was a sense of liberation as I just changed back into what I felt convenient and went home to shower instead.

Why is something as seemingly trivial as my haircut or hair colour such a big issue for him and in turn a trigger for me when he remarks to ask me when would I be cutting off my long hair. Its like I don't feel loved and supported, and I feel that I do not impose such things on him.

Its been coming up time and again and the thought of just breaking up and being by myself has been growing stronger and stronger even though in front of him I have been telling him that I love him.

What am I willing to give in?

He tells me that what I do with my hairstyle is not just a me decision but an us decision because I am in a relatiosnhip. This just makes me want to be single all the more. Because I feel like I do not have my own space and my own freedom to look how I want. As simple as that.