Welcome! Is this type of romanticised infatuation something you've been dealing with on and off over your life?

I'm glad its just sexual addition to this man...your first paragraph certainly didn't describe him as a pillar of the community. Knowing you have a new baby and a "very good supportive relationship with my husband" I would think a passing fantasy could happen but you would just get on with the other aspects of your life. If you are finding it hard to stop thinking of this person for sex, you may want to talk to a professional about it.