Re: I did both....
I was in the exact same position...well almost...we were not married, just living together...but for three years I was with the most wonderful, loving man I ever met. He was romantic, sensitive (he was a poet) and so in touch with his inner child that he made life seem like a wonderland, full of all night walks through the fog or snow, surprise pieces of antique jewelry, ...he even appreciated pretty clothes and liked to go shopping. But he couldn't kiss and sex with him was very tame. I had also fallen very deeply in love a few years before I met him (and was left behind) so I knew what the "whole package" was like, and that made me restless. To make a long story short, I left him for another and while I had the wild, passonate sex I wanted, very shortly I lived to regret it. (I mean in a month or two.)
Now, I am not saying this would happen to you...you are a different person with differnt karmas...but I never found another love of my life...and I never found another him. Now, at middle age, I have the privilege of looking back and seeing what a dope I was.
This is not to say that the needs of a 25 year old body are easy to ignore, but please keep in mind that "good men are hard to find", (and hard men are easy to find)and most relationships, once age cools them down (and it usually does...in one to five years) if they are successful turn into friendships.
What ever you do, do it gently and honestly, and try to keep the doors to a possible reconcilation open. A trial separation might be an excellent idea. You might sow a wild oat or two, and then find out that the grass is not as green over there as you thought it was. Or, you might find what you are looking for and set him free to find it too. There are no rules in life. Anything goes.
I have not spoken to the heart I broke since then, but via the internet I looked him up, and it seems as if he had two children. Knowing what a warm, people person he was, I am sure he ended up in a very successful marriage and he has a lovely family, something I would not have been able to give him, so at least for him, it worked out well....
Karma. You gotta love it.