That was a beautifully written, insightful and empathetic response mom2jess!
Not sure if you're into astrology Tricks2, however, i can give you a little insight into what is happening for your Capricorn girl.
Pluto (the planet of transformation) has started its 12 year cycle in Capricorn. This means there is a lot of change happening in everyones life, although particularly for Capricorns. This is a huge shift in the way she is aiming for things in life (Sun in Cap). The Pluto influence refers to things changing or ending to allow for new things to happen. It could be that she has been single for a long time and with you in her life this is making her change her thought patterns around how she would like to spend the rest of her life. Or... essentially there are other things she is dealing with of a personal nature.
It sounds like you're really into her, which is lovely, I suppose it's important to understand that when someone is going through such tremendous transformations, it's all new territory to them and this can be confronting, confusing, some people can feel depressed because they feel everything they have known is ending, what they fail to see is the positive side, which is the new beginning. Yes, these can be scary, but they can be exciting and full of endless opportunities. Hmm, my 2 cents worth?.... respect, empathy, understanding and attentiveness are great cornerstones for the foundation in any relationship.
You're compatability lies beyond your Sun sign (do you know where her/your other planets are?) Am happy to look them up if you wish, I will need to know both birth times and places.. I don't do diviniation.