Hi SomethingBeautiful...
Reading your post was like reading my own diary from 20 years ago :-( This might get a little long, but I want to tell you how the next two decades unfolded for me because my husband was saying all that same exact stuff before we married.
In my case, I was 25 and my boyfriend and I had been together for 5 years. He was damaged emotionally from a very difficult childhood which included abandonment of his family by his father while he was still a toddler, then further issues involving his brothers and mother while growning up. But he was a good hearted man and said he strongly believed in marriage and family as absolute committments based on how he saw himself and his family hurt by his own father. I felt the same but mostly because my family is very close with lifelong marriages throughout, and very few divorces anywhere in extended family. My boyfriend was very scared of making that committment himself, though, as he had mostly broken, dysfunctional relationships throughout his family. After we were together for five years and he was still scared to get married, I told him that I loved him very much and this wasn't an "ultimatum", but I wanted a family and children someday and we should go our separate ways if he still wasn't sure he wanted to get married. He said he loved me but still wasn't sure and that he agreed we should break up... it was agony for me but it seemed the best decision. We did so and had no contact for several months until he learned I was dating another man (I believed the break was forever and had completely moved on with my life, nursing my heartache privately, no contact with him or his family, or even our old friends together). After he discovered I was dating, he came back and proposed immediately, said he had been praying about it and really believed at that point that God meant us to get married. I believed him and was very happy.... we got married the next year when I was 26.... we had two daughters within the first 3 years... and then I wasn't happy ever again :-(
He never got over his committment phobia, seemed to be overwhelmed at family responsibilities, regular working at a married relationship.... and then he just "uncommitted" emotionally. He was still there going to work every day, and he loved our children, but he lived emotionally every day holding himself above our relationship as if he were still sitting on the fence trying to decide whether we should stay together or not. He completely shut down the emotional and physical aspects of our marriage, would rarely discuss it at all, and then just paid lip service to marriage counseling twice throughout the next several years. It was a nightmare. But he was a sweet, considerate "roommate", we had children who were very happy and he was a great father... I couldn't blow up our family just because I was so deeply miserable.
After almost 20 years of marriage, he said he couldn't stand hurting me anymore, didn't think he really loved me and asked for a divorce. More agony seeing my family disintegrate for good, my children confused and suffering, and I still couldn't get him to really talk about any of the reasons for it.... he really didn't know himself, just knew he was always miserable and scared.
After about 6 months of filing for divorce, pain and desperation trying to get him to talk to couselors and finally getting him to talk to our pastor, he came back and said he didn't think we tried hard enough to save our family and was willing to try again. Well, by then I had read several books about emotionally unavailable men, comittment-phobic men, and the reasons they have difficulty, etc.... A great deal of this all is related to how he grew up. We are now going through a marriage restoration program through a local church and it is helping a lot. I think he is finally actually committed in his heart to our marriage and family after 20 long years.... but there is a lot of damage and pain and work ahead to try to start over again. Our family is worth it, though, and all I can do is to keep trying to go forward and lean on God and try to follow His will for marriages and families. I do believe that He is helping immensely and I have hope like never before that someday I will actually experience a happy, stable, secure-feeling marriage.
Anyways.... I don't know what type of family history your boyfriend has, but after you have been together for 4 years it is making me wonder if he also came from a broken or dysfunctional family somehow that makes him deeply afraid of committment. If so, I'm not saying don't get married if he changes his mind.... just be very careful moving forward, go through some very good pre-marital counseling, and please, please don't have children together if you feel like he starts putting up emotional walls in between you even after saying he is ready to commit or you are married.
I'll be praying for you that your future is easier and happier than mine was... I can't regret the decisions I made because I have two amazing daughers I cherish, but my life has been such a painful and lonely one up until now :-(
God Bless both of you in whatever decisions or future you decide on....