One of the most destructive thing between Sam and I that underpins most of our fights is our incompatibility in expressing our negative feelings:

Sam's way - If he's ticked off, he uses cutting, challenging, fighting, and aggressive language. Words such as "lied" and "unsupportive" are not uncommon. Once he lets it out, he would calm down and try to be conciliatory again.

My way - Without anyone's influence, I usually take a neutral stance in my interactions with others. But I also reflect other people's emotions like a mirror. When someone gets aggressive at me, once a tolerance threshold is reached, I bare my claws in return. Once this negative energy has infected me, it will take a while to dissipate.

Putting our ways together - Sam gets aggressive at me even though I'm neutral. He pushes the right buttons and I start to mirror the negative energy. By the time he has cut me, I would bite back harder. Even though he might have already calmed down and is now conciliatory, it's too late to pull me back. The only way he could pacify me is to apologise and let time elapse. Unfortunately, some time during my cooling off period, he would have gotten frustrated and started digging into me again, which would then revive the subsiding anger in me. And the whole cycle starts again.

I have little doubt that if we ever break up, that'd be the reason.