I need more...

I've been married for 5 years and been in a monogamous relationship with my husband  for a total of 10 years. He's admitted to cheating on me twice over the last 10 years most recent was a year ago. I have not been with anyone other than him since I was 19 years old. I'll be 29 this summer and I feel my mind and body changing. I've never been unfaithful nor do I plan to be, but ever since our last mishap I just don't feel satisfied when we have sex. Not sure if it's mental bcuz I still feel the pain from his last adulterous act, or if I'm just tired of the same old dick! I mean honestly, I feel like I'm getting bored! I fantasize about sex with other men. Am I wrong? I haven't acted upon these feelings but I feel them gettin stronger by the day! I feel, I need more...