Since you and Simon retired together, there's not really much to do other than sleep, go out, and hit the gym. Si went every single day of the week, never missing a chance to go lift weights and spar.
He's not directly pursuing the perfect bodybuilder look; he's more after the strength and energy. If you ask him, he's not satisfied till he can lift the house with one hand. So he eats what he wants, works out everyday, and that's the way he likes it.
You stand by him as he uses the bench late at night, keys in your pocket. The man insists that you drive him home, since he's usually too burnt out to get in the driver's seat by then.
"All done, love. We can leave after I take a shower, yeah?" he hums, putting the dumbbells aside, and unwrapping the chicken sandwich he had in his bag, hungrily chomping down on the McDonald's staple.
"Christ, ye eat like shite, Ghost." Soap quipped from the Stairmaster, still busy walking on for what's been about an hour.
"Y' should go on a calorie cut. You'll look feckin' fantastic, muscles ripplin' like a cornfield. Be a bonny lad." he advised.
Simon chuckled, and finished off his juicy sandwich, and patted his tum.
"Nah, I'm good, Johnny. 'Sides, m' girl likes it, dontcha? The chub?" he smirks, giving your shoulder a squeeze.