Help with resolving fights

Hi everyone! My boyfriend and I have been together for almost five years and the vast majority of our relationship has been amazing. We love each other so much and have overcome a lot, we have a very healthy relationship. Or only big hang-up is how we fight. It usually starts with me being slightly annoyed about something and quickly snowballs until we don't even know what we are fighting about anymore. I want to work things out by talking but he shuts down and it's wholly unproductive. He doesn't wanna talk about it again. I wind up feeling like we have no resolution and he acts like nothing ever happened, but inevitably we have the same fight days, weeks, sometimes months later. I know many couples have this problem, so what advice do you have for me to keep things from getting out of control?

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Here's an example from last night to help give an idea of what we go through, and also I feel like I need to vent this out to someone.

He got a new job that is going to take a significant time away from us being together. We don't live together so we have set times to see each other. My normal work hours are 5am-2pm and his new hours are going to be 1pm-9pm. It's only a summer thing, but still I got very upset about this. I can't see us seeing each other outside of weekends. but it's a good opportunity for him. He thinks he's going to resent the job because I'm miserable about it so he wants to find a new job. I'm telling him no don't, but he doesn't want me to be unhappy. I also don't want him to be unhappy.

The thing is I'll be unhappy either way because I don't want him to give up this opportunity, but I also don't want to give up our already limited time together. We literally were fighting because we want to make the other one happy but both of us can't be at the same time. It went in circles for a while. I asked for some sensitivity to my feelings and he feels like he's been sensitive and that I've shot down everything he's said. "it's gonna work out" he said but I can't see that yet, and he couldn't even give me a minor solution. I want to be optimistic but my lifes history has taught me to set my expectations low so I'm not disappointed (not related to my relationship, just in general).

Eventually things quieted down and i just cried for a while because the night was ruined. Later we said our good nights and I love yous and he went home. This was the first 4th of July we've ever spent together because he's usually on vacation with his family this time of year and I feel as though it was a waste of a night. Today it'll be like nothing ever happened for him, but like I said, there was no resolution so I don't feel the same way.