How do i convince my boyfriend to try to work things out?

My boyfriend and I are just shy of being together for 3 years hes 20 and im 19. We live together also. The first year and half we were together everything was seriously perfect. We had small arguments that amounted to nothing and were resolved within like 10 minutes. Here lately he has become distant not so intimate (i.e. not wanting kisses, hugs, letting me cuddle etc..) But I know a lot of this is due to me because I over react in small situations and I overthink a lot of things. I also let my insecurities get the best of me. Its like a never ending cycle for me I let my insecurity get to me which leads to overthinking which leads to over reacting and then I snap at him. Well now that he has made it clear he doesn't want to be with me like this and I really do love him more than anything in this world I need to change my attitude. I need to go back to how I was when we first started dating which I know I can do because I am very determined at this point because I want this to work out. But how do I convince him to try to work things out with me because I am trying to fix myself to further fix our relationship?