Feeling very low

Hi All, I am a newbie and wondering whether you could give me some advice.

My boyfriend and I have been together for 18 months. We get on very well, I have never been so comfortable with anyone and I really thought he was the one. We both have two children from previous relationships and all our kids get on well.

We have had our problems along the way, as with all relationships and we find our way through them. But, and here is the problem, every couple of months we will have a big bust up. It will normally be triggered by something very small. We will have an arguement about it and a bit of a sulk. I don't bear grudges and am able to get over it very quickly and move on. My boyfriend cannot do this and he shuts down and cannot talk to me, look at me or touch me for up to four days. I try to talk to him and say that it's not worth dragging out and we need to move on, but he can't.

Our last arguement was at New Year on day 1 of a 4 day trip. The rest of the trip was awful and he said we needed a break. When we got back to his house after a very long train trip home, he asked me to leave. We didn't speak for 5 days and then I text him and said we need to talk. He text back saying that he thought things should just stay as they are for now as he is very busy with work and stuff.

It makes me feel very sad. Before new year we were looking for houses and now he won't talk to me. I love him so much and have no idea what is going on now or what to do.

Any advice?