It would seem that she is jealous that you put so much time and effort on the mud and not her. That you can be so focused on it and not her.
I know my GF just didn't understand the game, didn't understand the rush, didn't understand that there is an actual psycological bonding that goes on with these strange bundle of 1s and 0s that are characters.

I'll tell you what worked for me. I sat her down, told her I loved her, that I was with her for the long haul. I told her that like eveyone I had different sides, and one very important one for me was my creative and imaginative side. This was what I got to exercise when I mudded, she needed to understand that not being able have this cathartic release left me feeling unhappy. So if she really loved me and wanted me to be happy she would let me have time to do what I loved to do. If the roles were reversed I would want her to do what made her happy.

So best advice is always give her a kiss and a hug after you get to play CF. Might be all she needs is to know that the 'other woman' is not a threat to her.

Good luck!