Unfortunately, the relationship is a bit complex, They seem to truly care for one another.
But:
She loves sex. Him, not so much, Simply satisfied if he gets his 3 minutes every few days or a week. Her on the other hand, has been discovering her sexuality during the last few months. It started at the old apartment, and keeps growing and growing. From demure shy 'bating, once every couple days to what we see now. Latest advancement is the insertion of fingers. Rarely seen before except in passing. So let's enjoy the show, and hope for many more progressions.