Why do I continue to do this?

I've been struggling with a personal sin and I identify with Paul in Romans 7. If you were to read my journal/prayer diary you would see the same struggle that he wrote about. The desire to do what is right, but the impossibility to do it on my own. Here's my paraphrase of Romans 7:15-25.

Why do I continue to do this? I want to be a good wife and lover and yet I can't manage to do it. Instead I am selfish and greedy, the things I detest in others. If I can't manage to make myself a better person than God's law is a good thing, because it points out my short falls. It's not me that chooses this behavior, but my old, stinky deathsuit that I take with me. There is nothing good in me, at least not in this deathsuit that I am stuck with. I want to give myself wholly to my husband, but for all my resolve to do better next time I continue to return to my sin like a dog returns to its vomit. Why can't I just be the wife that I want to be? Why do I keep coming back to this over and over again? It's because of this deathsuit. It's the old sinful self that keeps popping up in me and causing me to to be selfish and greedy in my behavior. There's another power at work: for although my soul delights in God's law and longs to only do what is right and good there is evil that lives in me and keeps me from doing this. This evil is at war within me. It makes me a prisoner to my deathsuit and keeps me from being the wife and lover I long to be. AGH! I am such an ugly person deep down, I'm not the beutiful thing I want to be. Who can make me better? Who can clean me up and make me more presentable? Who can make me into the wife and lover I desperately want and need to be? Only through the blood of Jesus can I even hope to change. Thank you God for knowing this and for sending your son to make a way.