Very rarely does someone get mono twice or more than once.
So fortunately for most people they only contract mono once which is a good thing but not getting mono at all would be even better.
So while mono can reoccur it very rarely does and the Epstein-Barr virus (EBV) is what causes most cases of mono.
If you've caught mono once you still might be able to contract the mono again from someone else but it's very unlikely that you would get the mono again.