^ agree, and with the one above that. Fact is, it's none of his business. Period. It's in the past. If he were concerned about STD's then testing could be an option, but just rehashing past relationships he had nothing to do with and were pre-your relationship is intrusive; commenting on them, criticizing, or doubting you regarding them is insulting.

I too, wonder if there is something in HIS past he's hiding, that he's accusing you, but at this juncture, does it even matter? Tell him it's NOT his business and if he can't handle that, then letting this relationship fold of its own accord might be the way to go.

It is very difficult not to reference ex's....bad or good, but sexually, it isn't the 'present' bf (or gf's) place to question. Discovery between the two of you about likes and dislikes should be just that. Between the two of you. How you gained your education--or lack--is out of the realm of his perview. And as Bill3 says, if he's probing and doubting, he may not be emotionally safe to be with at all.

Take care