The green-eyed monster
I hear what you are saying about jealousy and everything else as our situations are quite similar. I used to get off on my wife playing/cheating in some ways even when it hurt. She was insanely jealous when I cheated and there was no upside for her. Cheating sucks.
We decided last year to try something different. We agreed to be poly, but I don't really want or need to be poly. She is 15 years younger than me and a total babe and we have incredible sex at home. But she does need to be poly. Now she has three boyfriends. I know them all. I still get off on her sexual adventures but mostly I get off on her total happiness.
The way I--I should say we--deal with any jealousy is absolute honesty. I can read her emails and text anytime and we always agree beforehand on what time she will be home from dates. She constantly assures me that I am her only true love and her main man and that if I ever ask her to, she would stop. I think stopping would be hard for her as she loves fucking her lovers, but I know she would. And knowing that she would stop if I ask makes it unlikely I would ever ask. Does that make sense?
We are totally digging this poly/mono lifestyle. It may change but for now it is great.