Is it bad that I've been thinking about cheating a lot lately?
Why do you think about cheating?
Just to look for a new thrill.
You should find other thrills in activities. Cheating is wrong and can hurt the person you are with.
It would be worth it. I just want to make her feel how it feels like to be cheated on and make her suffer.
If you really want to end your relationship you should do it the right way and not stoop to cheating while you think you both are together.