The "joys" of being in a relationship...

Sometimes I wonder why I ever felt like it would be a good idea to be in a romantic relationship with someone. Now is one of those times. The aspects of my partner that have allowed us to stay together for so long are now the source of much turmoil. I needed someone who could fulfill their social requirements without me having to go to social functions with them. Now, it seems, I have been cast aside except for certain "girlfriend duties" and being designated driver when he attends social functions. He works Monday to Friday, staying at his place during the week because it is closer to his work. He gets weekends off and stays at my place over the weekend. He mainly just sleeps at my place now and spends the rest of his weekend with friends. When he does hang out at my place, he just plays computer games. It wasn't always this way, we used to go out together or stay in and watch a movie, but we would spend time together. I'm not quite sure when this changed, but it has recently come to my attention.
So, being logical, I've been trying to figure out whether the turmoil I am experiencing is worse than the pain of ending a long-term relationship, or whether I am still benefiting in some way from this relationship beyond just avoiding the pain of a break-up. We have had several discussions about spending more time together and how important it is to me. The discussions always end with him promising to spend more time with me and apologizing for ignoring me, but nothing has changed. The discussion usually buys me 6 hours of quality time with him, but that's it.
Also being logical, I have realized that while I am depressed I can be a bit of a "buzzkill" and have tried to factor that into his behaviour. I understand that it is upsetting to have a depressed loved one, but I wonder if the lack of support in my relationship is a factor in my depression. I tend to be quite stubborn and don't take emotional utterances personally, so I don't believe that is a factor. Lack of support, and feeling like a burden, may be holding me back though.
So, as far as damage control goes, which is worse? Am I better off ending a nonproductive relationship that I have spent my entire adult life on, or am I better off trying to find a way to communicate my needs more effectively with the hope that he will become more supportive? That is the question, one that obviously can't be taken lightly. This will require a lot of thought and consideration.