how to stop arguing with my boyfriend?

[WOAh]

my boyfriend and i are very serious, weve been together for almost 3 yrs with many ups and downs. however, we stuck through it and are still trying to make it work. There is lack of trust in our relationship and it sometimes cause arguments. However, the major problem is when we argue it is so hard for me to let it go even if its nsomething so small. I feel like its really important to me, and i just don't know what else to do. He's completely opposite from me, he can get over arguments quickly and forget. So i don't know what to do.. i don't know how to argue right... I don't know how to let go of little things that bug me. I don't wana lose him.... i just want it to become easier... What things are important enough to wanna talk about it, cause i always want to talk about whatever is wrong and most of the time he doesnt. Please help us. and me more