Do you mean when she’s not working out with you? I would’ve thought a training partner would be enough motivation.
I used to train in the evenings and sometimes quite late, not I’m working on my sleep so my latest workout is a 7-8pm run, 5 or 6pm for indoor bike.
Tips;
If you have a tv series you are following, make the evening workout the time you watch that show.
Prepare dinner before the workout to eat afterwards after cool down
Have your bedtime routine sorted so you can shower after eating and go to bed smoothly and not be distracted by last minute tasks