What motivates you to get to the gym after a tough exhausting day at work?

I'm sorry for your loss: Hugs!

I went through a somewhat similar thing quite a few years back, when my husband died of esophageal cancer at age 45, when I was 42.

Everyone's experience differs, but mine was that the first weeks and months were really quite difficult: I felt numb and kind of rootless . . . detached, in a way.

What helped me was to be very firm with myself that I needed to go through the right motions, and ignore the whole question of "what I felt like doing" (which probably would've been sitting in a dark room staring into space). Emotionally, I felt like it didn't matter what I did, wasn't much enjoying anything, . . . so I might as well do things that would put me on a path forward into a positive future, when considered objectively.

It was a form of self-theater, empty gestures, or "fake it 'til you make it". (In my case, I was fortunate enough to know that that positive future was what my late husband would've wanted, because we'd had an opportunity, when he was ill, to discuss his hopes for my future.) No joking, it was an effort of will, in a context of numbness, for a while. Eventually, the numbness began to clear . . . .

Wishing you the best, and that you can find a path forward!

Are you in a position to alter your schedule such that you go to the gym in the morning? I don't want to go to the gym after a day of work either. Instead, I go in the morning before work and find that it's good way to get me going; I'm more energetic throughout the entire day.

Nothing motivates me faster and more efficiently than music.
If you work out in the morning, let your alarm be something that fuels you to get out and workout.
If you work out after work, have a playlist in your vehicle of choice -already set- that amps you up when you are headed to the gym.

For me, soundtracks (Mad Max, obviously, Two Steps from Hell, One Punch Man, etc) or music heavy on guitar, drums and swagger (70's rock like Led Zeppelin's 'Immigrant Song', or stuff like Rihanna, N.E.R.D., Tech9, ect) are sounds that get my body moving before my mind catches up.

Take a brief walk as part of your lunch break- it'll clear your mind and give you a boost mid-day.

Drink enough water. Keep a full water bottle at your desk. When it reaches below the midpoint get up to refill. Refill at the station farthest away from your desk, so you frequently keep your mind alert and your body mobile.

Reward yourself at least one session a week (or weekend) that is not gym-based. Like rock climbing, playing basketball, baseball, kayaking etc. If you can get together with other guys for this, that's a plus. Training the mind to view exercise as a pleasurable, daily experience can sometimes take awhile (versus merely as a tool to get results). For me, it took awhile to learn how to celebrate by going out and doing something rather than celebrating with food.

Lastly, get enough sleep. With lack of sleep, motivation, focus and work ability is drained. Your cravings for quick fuel will also be on an all-time high. Get enough zzz's and it will be much easier.