I want to cheat with a married woman for a year and I want to destroy her marriage
What about your marriage though?
I don't care about my husband, I want to cheat on him to become better in bed. All I desire is good life.
While wanting a good life is understandable, there are better ways to get this. People will call you a home wrecker if you go through with this plan and that can be hard to come back from.
It's hard to find a good girl these days.
I get that you feel that way. It might be a better idea to find someone who is single though. Being a home wrecker is not a title that you can easily shed.