My nan comes out with some wierd and wonderful stuff, albeit believeable, not nonsense, just untrue.
Doesn't mean she is not telling the truth though. None of us knew my aunt was seeing someone until she announced her engagement, similarly, no-one, not even her sister or parents, knew my cousin had had a baby until she turned up with an 18 month old. No reason for either to be kept a secret. It was also many many years before it was revealed another aunt's sister was actually her daughter.
I know they were someone not telling something but in general I find some people can be funny for all kinds of reasons.
Maybe he is married or of another religion or similar which presents problems in them being together.
You could always ask to meet the wonderful man you have heard so much about.