Worried we're just not compatible

Hi, I was hoping I could get some impartial advice from you guys! I've been in my current relationship for about 4 years now, living together for 2 and a half years within that (although we both worked and studied during that time so didn't actually get to spend every second together, it was just more important that we got to go to sleep next to one another at night). I moved away this September to start my PhD, and I've been having some doubts about our relationship. My boyfriend is the most wonderful person, so kind and generous, and he really does take care of me. The problem we've always had is that he never wants to go out or do anything, and doesn't want to see my family (he doesn't have a close relationship with his own family). Over the 4 years we've been seeing one another I can count on one hand the number of times he's met either my family or any of my friends. We have no real social life. He recently came to visit me and I tried really hard to get him to go out and do things because I hate to sit at home all weekend (he was visiting for 4 days)- I managed to convince him to go out one of the days for a few hours, going for a walk before meeting one of my coworkers and his wife for coffee. He grumbled a lot of the time we were alone, and then forced me to sit in the car for an hour as it was cold and he didn't want to go outside. The crazy thing is that when we met my friend and his wife he turned into this totally different charming person, and I was reminded of that man that I fell in love with. I realised that I hadn't "seen" that person in years. There was an opportunity the next day to go and meet up with another friend who I never get to see (maybe once a year) and he said he didn't want to go and that he came to see me and not my friends. I just don't understand why we can't do both, as it would only take a few hours of our time and we would only be sat at home watching TV. And it's not just since I moved away, it's always been like this, but I made excuses for him being busy or whatever. Recently one of my oldest friends got married and he didn't come, claiming he had to work. He also didn't come to my graduation for the same reason. He does work a lot but I feel like he could make the effort to plan ahead and book these important dates off. I love him, but when I look at my future I feel a bit like a bird in a cage. Like I'm always going to be choosing him over my friends and family. I don't dislike him for not wanting to go out, it's obviously just part of his personality, but I worry that we're just not right for one another and that in the long run we won't make one another happy. I love him so so much, I'm just coming to worry that we're just not compatible. I don't know how to talk to him about these things without making him sad, and it's so much harder as I don't see him very often (once a month) and it's hard to have these types of conversation over the phone... Essentially, I don't know what to do.... Help!!

If you are happy with him and you truly love him, then you will accept him totally for who he is, regardless of his personality. After 4 years, you will know whether this man is yours for life or he isn't. As your post states, if you're having doubts now....