Dear Roommate

Ok I need to complain and bitch for a moment.
I have had roommates for two out of three years that I've lived here, since I've moved out on my own. The first year I lived with two girls, then three girls, then two boys. Honestly, the two boys were cleaner than when it was all girls. However, I loved all of them as roommates and also as friends. We had amazing communication and worked out all of our differences. Then I lived in a one bedroom apartment. That year was pretty nice. Well, there was six or seven months of that year where I had a "roommate" aka live-in-boyfriend. Those weren't too bad either.
Anyways, my point is that this third year is not going so well with the roommate. I live with one male and one female. The girl and I get along great. Amazing. Fantastic. We communicate very well. We actually hang out. The male, however, is a completely different story.
A big pet peeve is dirty dishes in the sink. Maybe leave them there for a day or two, but not two weeks. My female roommate and I refuse to clean up his dishes. We have asked him several times to just rinse them out and put them in the dishwasher. Is that so fucking difficult? After two weeks?!
He has a dog. She is very cute but not well trained. She also doesn't get much attention from her owner. He does not have a bed for her. Cardboard is what she sleeps on. And my couch outside. She rarely gets bathed. He never lets her out of her cage except to let her outside for maybe ten minutes once or twice a day. She is out of her cage more when I am home or when my female roommate is home. She was out of food for almost three days once and her owner was feeding her cereal and crackers. She peed in her cage once and it wasn't cleaned up for a week. I feel so bad for her. But what can I do? I've asked him about it before and he basically blows me off, saying he will take care of it. Ugh.
Next. I like to have people over to my place to hang out. I don't do it often on the weekdays because I know my roommate works early on the weekdays. However, for the past few weeks, we have gathered at my place on Saturday night to drink and play some games. I let him know a day or two in advance. The first two or three times I told him I was having people over, he told me that he was having a friend sleep on the couch. So the first two times I said ok, we will take it somewhere else. Well when I came home the day after, quite early in the morning actually, there was no one sleeping on the couch. There were pillows on the couch with a blanket over them. Weird? Then when I asked him about it, he said they changed their plans. Right. So the third time he told me he was having someone sleep on the couch, I said fuck it, they can join us. That night, no one stayed on the couch, he didn't even come home. I didn't bother asking about it. Now he has been complaining to me about people being over that he doesn't know. When I tried to tell him that I would never bring anyone over that I don't trust, I got no response. I mean come one, why would I bring some random creepos over to his house, which is also my house? Also, he has people over a lot that I don't know, but you don't see me bitching about it because that's how it is with roommates. Unless you have the same group of friends, you will have people over at your house that you don't know. I've invited him to hang out with us so that he can get to know them so maybe he will feel more comfortable, but he always refuses.
Now the last straw is today. I'm sitting on the couch, chilling before I have to go to work. It's noonish. He is at work. One of the girls he has been seeing walks in the front door with food. She goes to the kitchen, then his bedroom. After a while she comes out and eats. Then she goes back to his room. He isn't even here! Are you fucking kidding me!? I know he would have a cow if one of my friends did that while I wasn't home. This is ridiculous.
Dear roommate, do not bitch at me for having people over that you don't know. At least I'm home when they are here.