I can't answer that for you but at least I could share my own experience. In life you can't have everything. People who try to have their cake and eat it too end up getting burned eventually, if not by being caught, but by the guilt that follows.
I was a virgin until 25. I got in shape and figured out dating, sex, and women, I had a lot of fun, traveling, having lots of sex, sometimes up to 4 girls at the same time on rotation. Really got addicted to the ego boost and I would say this time of my life was where I was most sexually fulfilled.
I'm marred now to a woman I'm happy with and have only had sex with her since we started dating three years ago. Honestly, I miss the times where I was having sex with lots of girls. Even if a lot of these girls weren't as attractive as my wife, it was the fact that it was something different that fed me.
Point is, whichever side you choose, you will look at the other side and wonder what it's like. If it were me in your shoes, if this is a pretty, loyal girl who has been nothing but good to you, you would be a fucking idiot to give that up. I've been with over 50 women in my life. A good woman is hard to find, just as a good man is.
Maybe my wife won't let me do anal, or ever do a threesome, or even be as attractive as some of the girls I've dated (though she's still fine as fuck to me), but out of ALL the girls I've met, she's been the kindest, most loyal, and most supportive, and there is no doubt in my mind there she is all in for me. Yes, I still wonder what it would be like, but it has more to do with my ego than my desire to fuck other girls. if I see an attractive woman smile at me or act nervous around me, I do wonder what would be the harm in going back to my old ways, but I always think of my wife and her beautiful face, and I realize how incredibly stupid that would be.