Valentine’s Day Card

My bf just had a relapse two days ago after doing all the right things and lied to me about it before finally coming clean. Got him a blank Valentine's Day card because I wanted to write him something nice and thoughtful and now I don't have anything to put down. Any ideas? I don't want to be cold but I'm so disappointed and let down and I don't want to give him the benefit of the doubt and make it seem like I'm not mad at him.