Why Do Women Stop Having Sex After Marriage?

Hello, I would love to read what your readers think about this.

I met and married my wife 7 years ago. While we were dating, being intimate was never an issue. We mutually always wanted to be on each other's body, so we practically did it ALL the time. But now, 7 years later, I am lucky if I get it twice a month. And we all know when things start happening, my woman will be the first to start looking for who to curse. Sounds funny but it really isn't funny at all.

Why do women do this?