Quote by Metilda
This isn't his issue or concern - its yours. If you didn't know of this guideline then how can he be held responsible? Afterall, no offense meant, but you were willing to hook up with a guy you met online and only aren't doing so because he's had 'gay sex'.
Only you are responsible for you.
Metilda hit the nail on the head. Who here has ever disclosed their entire sexual encounters to a new partner? In all honesty, have you told someone every blowjob, casual encounter, one night stand, long term relationship, etc? Case in point, he did not know you had never been with another woman before the question was asked, so if the roles were reversed and you had a woman/woman encounter, would it have been something mentioned early on in the dialogue? I highly doubt that everyone has been so forthcoming or even thought that your entire sexual past is someone else's concern. It's a different topic if you have a contagious infection/disease, in which case being open and upfront about it is essential.
I, for one, had no idea that someone would be precluded from donating blood due to having relations with someone who engaged with a person who had man/man relations. I doubt the chap in question would have known that his sexual part would be a hindrance to your future donations.
My 2 pennies.