Maybe I should have called it Married Single People. I'm sure you catch my drift.
There are tons of marriages, but many times the people in the marriage are not married. They are still single. They are still looking for another mate on a subconscious level. Maybe they've found something unsavory or undesireable in their mate. And not knowing it, they are now looking for what they want in a mate while already being married. This is dangerous, but the first step to overcoming it is to admit you are not happy and you are not satisfied.
The second thing is to find out how you and your mate can work together to remedy the situation. Marriage is a partnership. Never forget that.