I'm so glad that situation went ok for you. It sounds like he was a perfect gentleman and was really there for you at a time you needed him to be. That's great.
Personally, when you're ready to tell people, if you really felt you had to "explain" to anyone what happened, I'd be inclined to either say misdiagnosed infertility, or "these things happen!" depending on how well you know them
Good luck with your GP and OBGYN appointments, hope everything turns out ok