Mixed signals are common after a breakup, especially when you're really looking for any sign of hope as you are. He can blame his depression (if that's really what he has), but it doesn't change the facts:
- he has left and asked you to leave as well.
- he can't seem to decide whether he actually wants to leave or not.
- at the moment, you are not together and he seems to have no intention of putting forth the effort in working on your relationship.
Has he been officially diagnosed with clinical depression, or has he diagnosed himself? Has he sought professional help? Why did he only start complaining about the lack of sex after an entire year, rather than addressing it sooner? Why is he blaming you for his problems, like saying he'll have to quit school and work all his life (forgive me, but wasn't he going to have a job regardless??), just because you won't bend to all his wishes? I don't know how old he is, but that is something teenagers say to be manipulative rather than communicating like adults.
Flirting with you, showering/having naked time with you...these are things we hang onto when we don't want someone to leave us - I've done it myself. But the fact is that someone you love can tell you they're open to making things work, and they can say they care and want to meet you halfway...but in the end, you have to look at what they've actually done about it. In my opinion, this guy is playing games...acting like he still wants you one minute (to make sure he's impossible to forget), and then pushing you away the next. It's an addictive game to get involved in (I did so for the better part of two years), but it won't get you what you want.
Only he can tell you why he's acting this way, so I can't explain his true motives or feelings to you. My advice is to look at his actions rather than his words, and not to assume what he's feeling or thinking, because you can't know that. Perhaps you need to put your foot down a little, and stop responding to him altogether, as your responses only seem to encourage him to confuse you more. It sounds a bit like he wants to have his cake and eat it too: he doesn't want to be with you anymore, but he also doesn't want you to be without him because he's used to you being around. However, part of being an adult means recognizing the consequences of your actions (or lack thereof). He does not seem to have learned that.
Experience has taught me that you can believe in your relationship all you want, but this is a two-way street, and if the other person doesn't feel the same way, then there's not much you can do. May I ask why you feel you can have the perfect relationship?