Keeps bringing up my "ex"!

Hello Glow Coomunity, is this weird / what should I do about this situation? I have married the love of my life and I feel very happy with him. During a time where we were dating long distance, I became close friends with a male and although when he told me he liked me I cut off all ties with him, my then bf now husband was still suspicious and constantly asks me to explain the situation to him. After we talked for months about it, he finally let it go but still felt uneasy about it even though nothing happened. Now 2 years later he tells me he's been reading through old texts and some of the things I said sound fishy again. I'm soooo over it but I don't want to hurt his feelings of insecurity. What can I tell him to make him stop worrying?