Staying friends with an ex?

Has anyone GENUINELY stayed friends with an ex? How does your partner or husband feel about it?

Reason I’m asking is because an ex (we dated for like 3 months in college) of mine recently reached out to me after MANY years just to see how I’m doing and all. We ended things back then just because we felt we were MUCH better as friends and kept it that way but drifted apart.

Im actually happy to hear from him again. we both agreed we were and are better as friends and we learned and grew alot from eachother .

He said he would like to stay in contact with me because he misses our friendship, and honestly so do I. My husband knows and all and says I can do what I’d like because he fully trusts me- as he should.