I might lose him.

I've been dating this guy for 3-4 months now.. But when I met him I was recovering from a diffrent relationship. So now on ask as a joke I sent my ex "I love you" "I would tell you but you hate me" just so I could piss him off. But my boyfriend found out about it and I told him why I did that but he's still upset about it and I feel extremely terrible. I love him more then anyone but idk what to do.. 😭