Hi, this is my second thread.
Had a chat with DD when she got back from college and tried to ask her a little bit about her boyfriend. Didn't go down well that I had found out from her Facebook when we're not friends on there ('ARE YOU STALKING ME OR SOMETHING?') and only managed to get a bit of information out of him like his name, where they met, how old he is....I fear I questioned her a little bit too much about him as it resulted on her storming out of the room. Oops 
Managed to talk to her over dinner and told her that I hoped she wasn't staying at his house as it could be unsafe and I didn't like the idea of not knowing where she was- she denied that she had been (lies) and still refused to tell us more about him 'in case the relationship went tits up'...
Fair enough, I read everyone's points and I can't stop her having sex and the most important thing was that she was careful. She responded surprisingly well to this but I fear I fucked it all up horribly by telling her that I didn't want her staying over at her best friend's house (DD's boyfriend flatshares with her) any more as I didn't know the boy. As usual, she flew off the handle and we said a few things that we shouldn't have (her- I'm 18, I can do what I want, me- Not when we're supporting you through university, you can't). I also said that I didn't want her staying out all night any more as I couldn't trust her :(
Now she's not talking to me, one word answers, general miserable face. I don't know what to do. Sorry if you feel like you're talking to a brickwall MN, but I am just not comfortable with handing over a nice card and box of condoms and saying 'go have fun, kids'...although I know it's impossible to stop her having sex now I don't want to do anything that can help her do it in anyway- it makes me feel like a bad parent.