This is a pure guess, so take it for what it's worth.

You say she is not ready to have intercourse with you. However, you have done pretty much everything else except actual penetration. This doesn't make a lot of sense to me. She is comfortable enough to share sexual intimacy with you, but just not the penetration part. It seems like there's some sort of mental block there. Kissing tends to be a highly emotional thing that tends to lead people into wanting to have sex. If she has a mental block against having sex, the kissing could be getting her in the mood, but that triggers her mental issue against intercourse and she has to break it off.

Like I said, just a guess.