I don't believe there's a right or wrong answer here because different people are motivated to exercise in different way, so I can only give you my own motivation....
I dislike exercise too. I work all day... I'm often tired and just want to relax. Why should I waste precious time of my life running on a treadmill like some rat in a psychology experiment? And no matter how much I exercise, I already know I'm not going to be a beefcake.
But despite all that, I'm finally at the point where I exercise every day. How'd I do it? ROUTINE!
I completely concur with other commenter's suggestion of making it a habit, a routine, like brushing your teeth.
Find some time that you're fairly certain you'll always have free every day (weekdays and weekends both), about an hour. Force yourself to go to the gym. Bitch and moan all the way there but just go. Don't overprepare or overthink it, just go. I firmly believe just GETTING there is one of the biggest hurdles to overcome.
Once you're there, do something you think you won't despise. Try weights, try eliptical machines, bikes, running, swimming, jumprope, whatever. If you initially hate them all, give each one a few tries at least. After you've tried them, decide which one you dislike the least and stick with that. For me, it's running. I don't love running, but I find I can at least sort of zone out and just get it over with. But everyone's different.
When you've found your thing: Force yourself to go to the gym every day. Do your thing for some good minimum amount of time/distance you feel is a workout. For me, I started at running (more like a jogging-somewhat-faster-than-a-wak) a mile. I think I gave myself 20 minutes to run one mile a day and I just forced myself to keep going. I'd complain but I'd still go.
After I got more used to it, I upped the run distance and lowered the time, in REALLY short increments (like, a mile plus 20 feet), but it was all about getting it into a routine. Slowly increase whatever you do and make it your new baseline. Go a mile and a half, make it the new "regular workout." If you go less some days, well, so be it, but the next day, shoot again for your standard.
I started at one mile in 20 minutes and now I run four miles every day in forty minutes. Every day, including weekends, and it's such a habit I don't even have to convince myself to go anymore, I just do it.
I RARELY skip a day. When I do, the only thing going through my head is: "this is the time I usually go running... how come I'm not running?" And I swear to Buddha I feel guilty. You'll almost never see me post on SLOG between about 4:30pm and 6:30pm pacific time, because I'm at the gym - running. I still don't love it, but it's just a habit. It was hard to get there, but now that I'm there, I can't just dismiss it. I come home from work, put on my workout clothes, go to the gym, run my four miles, and I'm done. Habit.
Some people suggest a workout partner, but that never worked for me. I like to suffer alone.
My comment here might make it sound depressing or bad, but honestly, at this point, it's been a habit so long that it doesn't even bother me anymore. I just do it and forget about it almost immediately afterwards. It didn't take all that long for it to turn into a habit either, but you've gotta start somewhere.
I guess this is as long winded as the others, but it's a difficult motivation to achieve.
Habit, habit, habit. Just get your ass to the gym every day, even if you feel you're wasting your time there, just get there. Same time every day. Don't think about it, just go. Get it into your routine. That, above all else, is the biggest step.
Best of luck!