help me 😢😭

I did a horrible thing, I kissed a guy while I was with my boyfriend.
I love him so much it's unreal it was an in the moment thing .. I can't believe I did this I'm so ashamed. 
I told him the next day, he is willing to give it another try but he can't trust me. I want to show him he can! I know nothing like this will ever happen again I can't believe I hurt him like this !! 
How can I show him he can trust me when I've thrown the trust on the floor, I need help, I have get him to trust me again, I don't think I can deal without him 
I know that people will judge me but we all make mistakes I know how horrible I've been so please don't slate me I just need help I'll do anything!