This is a common problem faced by young couples. So you are not toxic. You just wanted to get payback. You have both cheated. Now that there is sufficient payback are both of you willing to work on it?

Trust, loyalty and fidelity are important if you want to move forward. I myself when I was your age went into nuclear revenge mode. It was a drawn out relationship that should have ended way sooner!

It is not about you earning his trust but both of you earning the trust.

What can you do?