Why am I having these thoughts?

I've put up with so much heartache and stress in my marriage. I've been the good wife for so long. Of all the crap I've dealt with, the smallest thing (attitude from my hubby) has left me wanting to be a bit of a bad girl now. I see a good looking guy and I get these thoughts and feelings. I've even thought heavily about an ex I really liked. My hubby has done wrong for so long, I think it's starting to sink in. What the heck is wrong with me? What should I do?