How to make a relationship stronger and closer ?

Me and my boyfriend have been together for about a year and two months now. However lately, we have been having a rough time. We have been having many fights. I don't wnat to leave him, I still love him so much. But sometimes he's a bit oppressing and over possesive. Even when it comers to little things for example like me wanting to dye my hair, he said I should'nt dye my hair because he would'nt see me agian until I dye it back. But right now I'm really upset because last time he was going througt his pictures on the computer to show me something and I saw pictures of girls he used to have a chrush on. I didn't tell him anything. I'm confused about all this. I got a bit upset even though the pictures had nothing ual or anything in them. Please don't tell me to leave him. I still love him very much.