Jeff was panicking over the implications of everything his husband was suggesting and his mind skyrocketed into high gear drudging up everything. Mark isn't so bad looking and his graying stubble and temples makes him look refined rather than just old, which is how Jeff usually saw him. Mark works so hard to support us and let us have the option for a romantic getaway. Mark pitches in and helps without needing to be asked, he really is a catch. He's the father of my kids and I love him so much. I trust him completely. He's trying to keep our relationship fresh...
Jeff was overwhelmed by how quickly his brain tied a million separate ideas of Mark together. It was as if the female brain tied the memories together with the "Mark is being sexy" thread and the more he followed the more memories were reexamined through the lens of a middle aged heterosexual woman. And with that, 'Zoey's' sexuality took Jeff from repulsed to ready.
Before Jeff realized what he was doing, he was dragging Mark to the bedroom. Mark's surprised reaction was cute and made Jeff that much hornier. Some fleeting concern reminded him that he changed his genetics and in this reality Mark is married to her/him... at this point Jeff's gender identity is just horny and willing.
Jeff looking at Mark through this new perspective was surprised by what was turning them on. Physique had always been overwhelmingly important as a guy but Mark's growing hairy beer belly, lack of huge muscles, and aging appearance were signs of what they had endured together and didn't detract in the least. Jeff found themselves with a flaccid Mark, who was caught off guard by Zoey's sudden ferocity. Zoey began giving head to get Mark ready and Jeff found themself enjoying the control they had over another person.
Mark was reduced to a moaning, whimpering ball of putty in Jeff/Zoey's hands and Jeff relished every squeak of pleasure and surprise. By the time they were done, an hour and a half had passed and they had moved to the shower to clean themselves.
Finally sated while drying off his womanly body Jeff realized that he had seduced and pleasured his dad and while in this form, really liked men, especially his dad... Jeff wasn't sure how he felt about that fact considering he had always been turned on by women and this level of eroticism was a surprise.
He could go back to the Chronivac, or continue playing the role of wife and mother.