I was going to post this as a response to a comment earlier but I decided to make a new entry. (Wow, 3 in a day. It's a madhouse! A madhouse!)
I've had two long-term relationships and several long distance relationships and with the exception of the last long term one, they weren't very satisfying. It's easy to get involved in a long term relationship but ultimately they're not satisfactory because there's no physical contact and I'm a very physical kind of guy. With my income there's not much hope of traveling very far very often.
My first long term relationship was my marriage. I don't want to discuss much of it right now because what goes on the 'net stays on the 'net. Let's just say that my depression set up some interpersonal problems that weren't able to be resolved. I needed far more emotional support than most people could give.
My second long term relationship ended with her breaking up with me which was a sudden shock to me. She came over on a date, sat me down and said it was over. She listed a number of reasons, and frankly, they all were based on my depression. She didn't say that my depression was the reason but rather she mentioned symptoms of my lifestyle that she couldn't deal with which were caused by my depression. I don't think she connected the reasons with the depression.
As for friends, I don't have any that are close to me, emotionally or geographically. I have a couple that are about as close as they can get, but I don't think they can take the full brunt of the depression. It's hard being alone when what I want most is a closeness that's really a fantasy.
I've pretty much given up on having another romantic relationship and I'm just not social enough to get any other kind of relationship either. Such is life.