I'm married..

I've recently started thinking about my ex.. on fb there is now memories that pop up and today one of my pictures of my ex and I popped up from 6 years ago and it makes me sad.. I loved him so much.. but he cheated on me .. like 3 months before I met my husband I saw him again and we kissed.. I don't think of him unless I see him or something that reminds me of him.. my ex and I always talked about getting married but things happen .. I love my husband very much and don't wanna leave him he's my life I 'm just so confused is this bad should I tell my husband.. I'm 21