Kim I was in a similar slump for a really long time.
I used to LOVE and look forward to exercise sessions. I never needed will power. And then I hit the slump!
When I stop exercising regularly, everything goes downhill. I eat badly, sleep late and feel sloppy.
The big obstacle for me was that my past exercise habits made me feel I needed to do a LOT on intensity+duration+frequency. I could not summon up the enthusiasm to go back to the high standards I had set for myself.
After some time beating myself up with ambitious rotation plans and guilt for bailing out, I "let go". I realised that what was not working for me was trying to go back to the same intensity and duration of my prior workouts.
My suggestion - Do you dread working out because it is more of the same routine? Then try something new like yoga/pilates, working out at a studio/gym, walking/running. Do you dread the duration? Try shorter workouts? Do you dread the intensity? Try gentler workouts. Workout fewer times per week. Workout at a different time of day - try coming up with a schedule that you feel you can stick with at a minimum. Even if this means say, selecting Sat + Sun + 1 working day a week to commit to exercise.
Once you are back on track with sticking to the "minimal + fun" workout schedule, the urge to up the intensity or go back to earlier formats will return.
Meanwhile, exercise will no longer, hopefully feel like a chore.