Hello, MBRetzlaff, and
to GaySpeak. Sorry I've not been around earlier for this. Now that things have been decided, you can start considering what you said in your original post, that is to say, that you don't think you ever loved him.
So this relationship was never what it should have been, or what you hoped it would mean for you. You've made a move that'll free you of this relationship and that will goad you to move on to something new, something more meaningful. It may help you, also, to reconsider your position with regard to fidelity and what it means to be in a relationship where each one has enough freedom to express not only their emotions but also their need for sexuality.
Was your partner considering cheating with you, or had he actually done it? You don't need to know, probably, but maybe you can give yourself the honour of forgiving him (if he's erred) and give yourself time to forgive yourself for making the mistake of assuming your relationship was the "right one for now". You've settled for less than you wanted this first time; you may consider settling for something similar in the future, but you'll know the conditions and not feel you've been fooled. It's always hard to lose one's innocence, to some extent, even if it brings us better understanding of others and ourselves.
We learn from our mistakes, and those of others. Hopefully this is a way of cleaning the slate and starting anew but with new wisdom.
Hope you recover quickly and find a new purpose in your life.