I'm a 19-year-old woman and I find myself getting upset with my 18-year-old boyfriend over both minor and major issues. How can I manage this more effectively?

Recently, I've noticed that my boyfriend seems to be pulling away from me, and I believe it’s linked to how I manage conflict in our relationship. I get upset not just over minor issues but also about ongoing concerns that really bother me. For instance, I've asked him to stop making insensitive comments about my appearance, frequently checking out other girls' Instagram profiles, and treating me as if I'm inferior in certain situations. These behaviors genuinely upset me, and when they occur, I react with anger because I feel disrespected. I'm also exhausted from having to repeat myself and continuously ask him to make changes. However, when I do get upset, I struggle to move past it and often end up having what some might call a tantrum. Even in times when we could resolve the issue, I tend to prolong the argument, which escalates to a point where I start to feel guilty for overreacting. I recognize that this behavior causes him to withdraw, and I don't blame him; he’s a good boyfriend in many ways, and I can see how my anger and tendency to hold onto grievances are impacting him. I want to learn how to express the things that hurt me without losing my temper or making him feel more distant. What strategies can I use to manage these conflicts in a healthier way so we can strengthen our bond? In short, I find myself getting really angry at my boyfriend over both minor irritations and persistent issues I've requested he address, like making jokes about my looks, obsessively browsing other girls' Instagram pages, and treating me as though I'm less significant. Although my feelings are valid, I tend to prolong arguments until I feel guilty, even though he is a good boyfriend overall. How can I share my frustrations more constructively without escalating situations or harboring resentment?