Boyfriend stayed in a hotel room with another woman?

Why are you still with him is the real question.

Was the rest of the family staying in the hotel room, too....or was it just him and her? If it was only them....then you know what happened. If several were sharing a room, then it was probably innocent.

I would be upset too. This is inappropriate and borderline cheating. He is disrespecting you.

If he was up to no good, wouldn't he have hidden her from you? The fact that you saw her right there and she didn't seem to care that he was talking to you, makes it sound pretty innocent. I don't know how it works in Italy, but in many places, it's not easy to just ask for another hotel room. Reservations have to be made weeks or months in advance. Could it also (possibly) be that he was supposed to share a room with his brother, and the brother's gf was supposed to share with her sister, but his brother & brother's gf wanted to be together (without parents knowing)? If it continues to bother you, let him know. "I know you'd never cheat on me, but I'm just jealous of any woman who gets to be alone with you. Wouldn't you feel that way if I was sharing a room with another guy?" Try to stay lighthearted about it, though, because what you don't want is to be the nagging, distrusting, far away gf while he's sharing a room with someone who's not nagging or distrusting and who is nearby.

Yup- that's very fishy and sneaky on his part.

You know what? It's time for a break up! No trust = no relationship.

Oh God is he messing around with you. The fact he couldn't give a good reason for why she was always in the same room suggests he was up to no good, and it's disgusting that he would invalidate your feelings like that. You already told him you weren't comfortable with the situation, and a caring boyfriend would've acknowledged that and not crossed those lines again. If you want to try and gather more information about the situation then I wouldn't stop you (it's good to be sure), but it does sound to me like his intentions aren't good.

you are making a mountain out of a mole hill and by doing so, you will damage the realtionship beyond repair.

If you are this distrustful of him., then there is no foundation of trust between the two of you. I'm not saying that is your fault, but be honest, would your reaction have been any different if he told you before hand? Somehow I doubt it and I wouldn't blame you. If your boyfriend thinks that sleeping in a hotel room with another woman regardless of who she is, is appropriate, he is an idiot. Having said that I wonder what else Mommy and Daddy failed to teach loverboy? I'm just saying. Is this the kind of man you actually see a future with? If your answer is yes, then I have to wonder what is wrong with you? Sorry for being so blunt but I don't believe in dancing around the truth!

me thinks they are fornicating

You have every right to be upset and it sounds like he might have been up to no good, because his excuse for not getting his own room is very lame.