Anger and resentment towards family member

There's a person within my family I can't hardly stand anymore. I just feel like they're a selfish person who doesn't care about anyone but their self.

We were pretty close until a couple months ago, and still talk on a regular basis. The thing is I just feel taken advantage of by them, like they never care how I feel, and take advantage of my good nature. They act like were on some team and are supposed to look out for each other, and that pretty much equaled out to me going out of my way and them never really doing anything out of reach on their end. I started feeling anger and resentment toward them a few months ago, and pretty much stopped doing things for them completely.

Without going too much into detail they did something really petty that they knew would upset me, didn't seem to care, and tried to hide it. They've done some things to really upset me before, but this was final straw. The moment I found that out it made me feel very unimportant to them, and I was beyond furious. I confront them about it and they deny any wrong doing in what they did, and they stayed like this for about a week. When I was finally able to confront them they admitted they were wrong, I completely unloaded all of my anger and every thought I had, in the end they seemed saddened and said they felt bad. The thing is this was a day before a thing they wanted me to go with them, and looking back I think it was probably all a manipulation to get me to go with them.

It's pretty much impossible to talk to this person about problems. There are times when they know they're wrong, deny everything, and dodge around it. Then there's times where you can confront them but they and then say something like "I won't do it again" in a tone like you're supposed to feel sorry for them.

I don't know if they listen at all to anything I confront them about. I'm not at all a short tempered person, and only tell a person some things bothering me after a lot of dealing with it. Usually they'll stop doing something, and then go back to doing it because I'm not constantly talking about it. There's only one bad habit of theirs they stopped doing completely, and of course they always bring it up like it's some kind of accomplishment.

We live in the same house, so there's no way I can get away from them. I just can't stand them any more. There are times where I don't feel anger, and then times where I feel nothing but anger towards this person and I'm tired of it. What can I do about these feelings of anger?