Does my boyfriend want to end it?

So me and my bf have been dating for four years. First two were perfect then last year he went on a year abroad. Obviously the time difference made it difficult but we had very different expectations of what was a reasonable amount of time to be talking and it definitely put a strain because I felt like he wasn't as interested as I am.

Now we've been back in the same place since the start of the academic year but we've really been arguing a lot and over the same things. One of the main things we argue about is that he doesn't want to have sex anymore and I don't know why. I've not tried to force him or anything but he can see I get annoyed when I'm asking all the time and he's saying no. To make things more confusing he says he still wants to but then we never do.

Another problem is that he's not telling me important things and says it doesn't matter. For instance, he got a job offer and just didn't tell me. When he eventually told me I was really pleased for him and then I spoke to him afterwards about how it had upset me that he hadn't told me straight away he told me it was nothing to do with me. I think it should be, especially since it could mean doing long distance again.

So what do you think? I'm really starting to feel like he wants to break up with me but just isn't brave enough to do it. How can I let him know that I can't do this anymore unless he changes without it being manipulative?