Both men and women have major crushes on multiple other people that can last a lifetime. That doesn't make them a threat to their marriage/relationship. There IS a risk to the relationship when the partner asks them to give up that crush (which is not even possible, as science tells us that reward pathway/association gets cemented in our brains).
The correct advice is to recognize your own insecurities, identify if this is about the crush or about you, and recognize that your partner chose YOU.
Don't force them to choose again. That's a gamble you might lose.