Your GF is more secure with you, and know that she can say no to you without feeling, how should I say, afraid that you would get angry or something.

The thing is, some girls are really insecure. And sometimes they have sex with guys not because they really want to, but because they feel that they need to. It's like they don't dare to say no because of reasons I don't understand myself, so they just go through with it.

I know my girlfriend (That's why I'm using a throwaway.) had sex with a guy when she was younger. She thought the guy was cute, but she didn't like him in that way and she didn't want to have sex with him. Her friend kept telling her to hit up with him but she kept saying no, so the friend talked to the guy instead and said that he should make a move on her. One thing led to another and they ended up having sex later that night. He thought my GF was into him and wanted it, my GFs friend probably thought that she helped my GF getting something she wanted. But my GF was not ready for it, but for some reason she was afraid to say no to the guy, so she went through with it without really wanting to, and not really feeling it.

I don't know why she didn't have the guts to say no, she tells me she was insecure but she herself doesn't really know why she didn't dare to tell the guy she didn't want to have sex with him. I can only speculate, maybe she didn't want him to be upset, or maybe even angry, maybe she didn't want him to talk shit about her with their friends and give her a bad reputation.

Anyways, this became longer than I thought, I just wanted to give you a view about how girls can sometimes thing. Regarding your lines about why girls doesn't communicate to a guy if they don't like something that's going on.