I've (36m) been with my wife (34f) for almost 20 years, we started dating as teenagers. Since we started dating, another guy (let's call him Tom (35m) has had a serious crush on her. At that age, we were rather standoffish towards each other. 5 years later, me and my wife were in college and Tom still had a crush on her. At that point we both thought it was extremely bizarre, but he wasn't threatening or stalking her by any means, so we sort of kept a hands off approach on it. We didn't came across him much anyway, and he didn't go out of his way to see us (we shared some friend groups, but that was about it).
Almost 20 years later, Tom still has a crush on my wife. He's got a wife and three kids, and appears to be a great father, but he can't shake the crush. We live in a relatively small community, so we do run into each other occasionally. The guy is a completely muscular, biker looking guy and he turns into a nervous teenage boy when my wife is around (glancing over at her, slurring his speech if they talk, nervous gestures and shyness). Even Tom privately told me he thinks it's extremely bizarre that he still likes her, and he respects us and would never treat us disrespectfully. Despite the bizarre dynamic, we all have a respect pact between us when we cross paths.
TL;DR Has anyone had a situation where a guy has had a crush on your wife for years, but is decently chill about it.