On the opposite side your partner has a very hard situation to deal with. They see you're working hard and you're stressed, but you come home and just want to be left alone, you're snappy and easily annoyed and they get scared away from you. They also see you keep working or messing around on the computer in your free time and think that you don't really need to be doing that and could have more time to spend with them, but you're choosing not to. They don't understand your brain is stuck in computerland and can't just switch over to the normal world so easily.
For a relationship to work you have to both be working to make each other happy. If one person isn't putting in effort it doesn't matter how hard the other person works. It's a partnership, an agreement to have fun. Hell, most ways of "having fun" are like that. If you go to any event - a parade, a party, whatever - just going is not really much fun, you have to go in as part of the group that is cooperating to be a fun group; you're sort of becoming part of a performance group pretending that it's more fun than it is really is. If you all go along with it, it's a blast.
For all you geeks out there, it's like playing D&D. The party and the DM are making a social contract to try to get into the spirit of the game and enjoy it. If you just follow the rules and go through the motions, it's no fun. If you get into the spirit but everyone else doesn't, it's no fun. You need the DM to try to give you interesting scenarios, and you need to give him feedback that you are pleased and amused by his storytelling, and then you also need to contribute mirth and creativity in your actions.
Something that I often fail to do is give enough feedback that I'm enjoying what someone else is doing for me. The pleased reaction is just as important as the original kind action; by being a couple you're agreeing that when your partner does something nice, you will reward them by being happy because of it. If you are hard to please or inscrutable, it's no fun to try to make you happy, and you can't have a relationship. The relationship must be a series of back and forth mood enhancers. I do something to make you happy, and you show you like it; you do something to make me happy, and I show that I like it; back and forth forever. ))<>((