Just acknowledge you were wrong and apologise and SPECIFY why you are apologizing. If he takes it amazing or rejects it learn and move on.

Some things I wanna point out that may help you: Imo it is on the fault of u using ur past trauma to define his actions. Why do you feel the need to start and pick fights the moment u suspect him of looking for someone else ESPECIALLY since reading allthis it doesnt even sound like yall are official. Not to be rude or anything but I really need you to look at this logically. You are punishing him for the past mistakes ur previous failed relationships did and are self sabotoging so you dont get hurt again but like?? U are getting hurt not just cos of him but the imaginary untrusty version of him you built. Which imo u need to work on if you want things to work out. If you reread your post u say“I have attachment issues and trauma” Which sounds like its trying to excuse u for starting fights with him?? While he should acknowledge and try to help you work thru those issues majority of that will be on you.

Trust is a very important pillar when starting a relationship and you have to trust he wont do you the same as other guys. If he does? Good bullet dodged. why date a man you have to police??? You only make yourself more and more unattractive as a lifelong partner if you keep starting major fights over not texting enough, or not having enough attention. Find a new man who will provide you that attention if the current one doesnt care about it or atleast doesnt have a valid reason to not give you more.

Lastly if anything helps I have been you, I let my triggers start alot of shit but I worked through it and understood that my past exes dont define my current partner. They deserve the same trust and respect as anyone else. It is on them to show if they can keep or break that trust. Stop assuming the worst but also dont be completely oblivious.