Did I just get cheated on? Advice needed ASAP

[Pacific]

One of the more concerning things here is that you say he wants to apply different rules to you. He is allowed to do this but states he's uncomfortable if you do the same. That is a maturity issue and may be something to seriously consider when thinking long-term.

[Darius]

GOOD. I hope he enjoys himself all the way!

I doubt you would have started this tread if you really felt this way.
You stopped hooking up with other guys because you felt this relationship was meaningful and I imagine you hoped he felt the same way.

People are usually on their best behavior when a relationship is new and exciting.
Don't you have to wonder if he will ever be able to keep his pants on? Will you be okay with that?