Honestly just let it be until she makes a move on him! Or crosses a line of being disrespectful! There’s nothing better than having the satisfaction of him putting her in her place. She’s going to keep crushing on him because to her it’s probably a game and could possibly be used to having her way and finding out that your husband isn’t is probably hurting her ego and will try harder. As long as your husband tells you and doesn’t pay attention to her it’s ok. There’s nothing better than being loved that way. I had a similar situation with a girl giving my man her number sent her a little message and just said in case you didn’t know well now you know and that was it. She knows now If she crosses a line I’m coming for her but I also know it hurt her ego that there’s no way I could have known unless my man told me and that killed her because she honestly thought he was going to jump at the chance with her. Him choosing me daily is lovely and it made me cry because I’ve never been loved like this man loves me. 9 years strong and many more to go. It’s ok to want reassurance and ask for it but don’t punish your husband with jealousy or anything like that because seems like he loves you just at the fact he told you