Quick, somebody call in Greg Behrendt!
I can understand that you love him, you put a lot of effort into the relationship, you had hopes, you were committed etc etc and that can complicate what should be blaringly obvious. He cheated on you. To me that is just shitting all over the relationship and all those feelings you have for him.
Stop thinking about how much you love him and start asking what in his actions have indicated he loves you back? I dont think you could ever include cheating as the actions of a person in love.
You deserve to be with someone who is faithful. You deserve to be with someone who can be trusted, who will never want to cheat no matter how many ups and downs there are, who is committed. That's not being too optimistic as you called it. That's knowing your goddamn worth!
What would Greg say? You're too damn fantastic to waste your time on someone who is clearly just not that into you!