Breaking up with my bestfriend

So I guess for a bit of context:

My boyfriend and i have been together for almost 2 years now. It may not seem like a lot of time but weve been through so much together it feels like an eternity. About a month ago I started to feel much more frusterated and upset than usual, I would snap at the smallest things. I didnt realize how badly this affected him until about 2 weeks later. Now for the past 2 years we have gotten to know everything about each other. From having difficult childhoods to never having anyone there for us growing up. During the time of getting to know each other we slept in the same bed at my home, started to take showers and baths together, because more intimate, and both switched to the same homeschool. We would wash each others clothes, fold them, then put them away. Make breakfast and dinner for each other, and we always tried to do something fun on the days i dont work. So we are basically in an adult relationship, as teenagers. So about a month ago I took a trip to california to visit some family and during that trip we hardly talked, and everytime we did talk it was yelling and arguing over the phone. I was hurting so much and there was so much pain involved but i never gave up. The night i came home from the trip he spent the night with me we took a shower together and i made us breakfast. Everything was fine. Within the next few weeks hes started to become more and more distant and says he wants to move on. I know I can fix it any help?