This seems to me like a case of one-sided dependance, as you have seemed to have figure out. A good relationship is symbiotic, meaning both partners help and rely on each other for mutual benifit (AKA, being happy together and helping each other out). What is happening right now is you have givin him the idea that no matter what he does, its fine with you. This might have happened because you said you do nice things for him and act happy all the time, while on the inside your torn up. This actually will make him lazy, thinking that he doesnt have to work to keep the relationship going, which might be what is happening now.
I know that we all want to shower our snuggle-buddies with gifts and nice happy lil things
It not only makes them feel good, but it makes ourself feel good because they feel good. But, like with the computer, his gratitude did not last long, thus making your gift a seemingly worthless endevor. What you did with that computer was very, very, very nice =D I wish i could put together three computers into one >.< But, just the effort you put into that is enough for anyone to be grateful every time they use it. His problem may be the relationship laziness, where he consciously or subconsiously believes that you were obligated in doing that for him, which is far from the truth. By every right, you should have gotten the new computer, but out of your love for him you offered it to him. And in return, you get nothing but more stress from him.
I know this sounds kinda weird, but in a relationship, the partners need to train each other a bit =P Say, for instance, that i dont like mexican food. My girlfriend brings home a buncha tacos and anchalattas or whatever funky food there is and says "Eat up". Well, i got two choices. I can eat it, say nothing, and get my hated food over and over and over again, or i can speak up and say i really dont like it, can we have some chinese food?
It seems like an easy choice, but only in practice. Subconsiously, we all think that disagreeing with our lovers will cause them to become upset or sad or angry at you, even if its the little things. This keeps us from speaking up, and thus we recieve the same treatment over and over again, in this cause more tacos -.- The only way to fix this problem is a simple, yet very tough, conversation about how you feel about it.
Yes. Every relationship needs to talk about thier feelings. It sounds girlish, but i am a guy and i know how important it is. Without that connection of someone understanding and comforting you on how you feel about the world, your connection as buddies becomes just in name. Every week at least, you guys should sit down and talk. Actually, every day would be better
But it can be talk about anything. But once in awhile, you gotta talk about how you feel about things! Don't get angry when you talk about how you hate it when he leaves to toliet seat up, or when he leaves dirty clothes strewn about the house like a tornado hit it. Just calmly tell him the things that annoy or hurt you, then offer up an alternitive. Then ask him what he thinks about your solution, and if he disagrees, converse until you both can come to a sutable and comfortable solution, together. Also, if he is relucant in changing his ways, ask him about something he wants you to change. Like how you vaccume the walls every day or try to flip ten pancakes and only one gets to the table =P
I warn you, however, dont tell him "I hate it when you treat me badly". That hurts his feelings, and in turn, he may get defensive. Tell him that you cry alot when he hurts your feelings, or ignores you, or does anything else that makes you feel bad about yourself. Be gentle, yet strong in what you say. If he says "No i dont act like an ass", dont say "Well, i GUESS you dont act like an ass then..." No, you have to stick ot what you say. Its tough, but its a kinda battle of wills. And for a long time, his will has dominated over yours, instead of both wills working together. But remember always to be nice about it. Never intentionally hurt his feelings. And if you tell him about the computer and all the other things and how it made you feel, he will not get offended unless he has anger issues. Which i dont think he does, hes just lazy =P
Espessially talk about the moving issue. That is probably the most important event that is coming up for you guys, and thus need to be talked about. Tell him how you feel about everything, and then say how that makes you nervous about moving. Just keep your cool, dont bend your needs to suit his, and be brave. Its really hard, i wont lie, but it will insure your relationship will not die out like so many others. All you need to do is talk and try to keep the romance alive.