I get that a head's up is nice when you know you're on your period. Although I can also imagine that it's a difficult subject to talk about when you haven't known the person for a long time. However, I am surprised that you/he only realised it after foreplay. Weren't you using a pad or a tampon, which in itself is a warning?

I don't really agree with the reactions about it being foul or people being squeamish about blood. A head's up isn't always possible, for example when you unexpectedly start your period or when it's your first time and you just happen to bleed or because the sex was a bit rough which can also cause bleeding. I get that it's not something you would expect, but please realise that it's not like we enjoy bleeding or that we do it on purpose. It doesn't really help being humiliated because of it.