How do you deal with your own lust in marriage?

I (M) am reaching my thirties and have been dating this woman for roughly seven years. She is gorgeous, caring, and fun, and there are not many things in life that bring me as much joy as making her smile. Recently, I decided that I should ask her for marriage, but some thoughts have been coming to mind since then.

They are mostly related to lust. We're in a monogamous relationship, and whenever I see a beautiful woman around, thoughts of lust come to mind. I know these thoughts are natural to a degree, but they are immediately followed by a sense of guilt and a feeling that I'm disrespecting the woman I want to marry as well as our relationship.

For the married men out there, how do you handle thoughts of lust towards women other than your wife? Do they bother you?