How can I tell the love of my life? Please help

Ok, I'm going to try to make this as short as possible, and I hope that some of you wiser and more experienced can share your insight with me. I've been in a relationship for many years now and I love my boyfriend to bits. Due to academic/ job reasons, we have not been able to live together or even in the same city for a few years, although we've taken breaks from the long-distance thing and everything works perfectly when we live together and share enough quality time. But anyway, like I said, for the most part of our relationship, we've only been seening each other a few times a month. The rest of the time we led separate lives and keeping in touch wasn't easy because he doesn't like talking over the phone or texting much. I have told him many times that this bothers me, that I need daily contact, but he says it's his way of coping. Anyway, I won't only blame him for this (it must be my fault at some level too), but I've come to feel neglected VERY often. I've come to think that he doesn't love me, that he's with me simply because he doesn't want to break my heart. Then,he when we're together he proves me once more that he loves deeply and I realise that I've been an idiot for thinking otherwise. Anyway, this communication issue has distanced us very much. I used to have a lot more free time than him and, to cope with the loneliness, I tried to meet new people and go out whenever I could. He knew this and was ok with it, and I've introduced him to most of my friends and understood that it was part of my personal development. Anyway, a few months ago I met a new group of people. They were kind of bohemian and friendly and we began meeting regularly for beers/ playing sports/ etc. I told him about all of this, of course. There was this guy (let's call him C) that at first I found 50% interesting- 50% annoying, but we finally got along and I began to feel attracted to him. I knew he was interested in me physically (I told him right away that I was in a committed relationship), and I think I enjoyed the attention - so much that I got confused. Thank God, I realised soon enough that I did NOT like C at al, that I was just projecting an ideal, and my infatuation gave way to a friendship of sorts. At this point, I was feeling neglected by my boyfriend, and this little idea that we might not love each other, that we might never be happy together, started creeping into my head. Otherwise, why would I be paying attention to a lazy, dirty, drug-abusing, puerile and emotionally immature person? It was RIDICULOUS. My boyfriend is everything I love and look up to and I knew it, but maybe we couldn't get it to work. I was truly missing some joy in my life. Anyway, I never even as far as kissed or held hands with C, nor toyed with the possibility of it. I never flirted via text message or anything. I never told him about my relationship concerns. I never considered cheating - that is out of bounds for me and I would never break my boyfriend's heart like that. He said he wanted to find a life partner and I even encouraged him to do that. What this has taught me about my relationship is that it is lacking in intimacy, sex, trust and commitment - and most of all, quality time. I realised that we need to work on these instead of giving up. In fact, since we're spending more time together, everything is going great between us. I feel as if I payed this guy, even if for only a short period of time, the kind of attention that only my boyfriend deserves, and I feel guilty. I also feel guilty for wanting to leave while he was fully committed. He has been kindly waiting for me to finish my qualification and now the time has finally come to move in together. I feel compelled to tell him to begin solving our communication issues and to get rid of the guilt. What should I do? Should I tell him, or would I only hurt him and make him lose his trust in me? How should I approach the subject? I'm experiencing a lot of anxiety over this and I'd appreciate any kind of insight. Thank you for your time!