I think what you are looking for is the motivation within yourself. No one else can give you that. YOU have to REALLY want to do it, and you likely have to give up something else in order to succeed. You have to (or at least I had to) make it a priority and just do it.
When I started I made working out (and soon after, nutrition) my first priority. I passed up going out for lunches with co-workers, I stopped going out for drinks and wings as often in the evening. I say no thank you when treats are offered by friends and at work (even though I sit 10 feet from the table everyone leaves all their desserts, etc). I started dating people who would rather go for walks or on hikes or playing a sport, rather than movie and dinner dates, and many, many times I said I couldn't go to 'random passive social event' because I had to go to the gym or do p90x or run, etc. I also stopped hanging out with friends who were not helpful towards, or worse, detrimental to, my quest, and started hanging out with motivated physically active people. I stopped doing overtime at work so I'd have time to work out, but to be fair that was easy since management was also trying to get us to do less. I started ignoring the voice in my head that said - too tired - not enough time - you're not good enough - too much work - too sad - too hot - too cold - you'll never succeed - what's the point...
I'd like to say it wasn't easy to do... but really, once I made that my priority, it was not only easy, but addicting. I spent a year or more, like you, waiting for that motivation to start and wanting to get in shape, but not really wanting it enough to actually make the effort.
Another thing that kept me motivated after I started was tracking my progress each week on a graph. Every Monday I weighed myself and added it to the graph. Sometimes I went up, usually I went down, but over time it was stunning watching the general trend of the graph. I started this about 3 months before I actually got moving, so it may not help you get started, but it sure helped me keep going through the times when I started to lose motivation. Highly recommended.
Find your goal. Make the effort. It'll be worth it.
Oh! One other thing that might help. Start small. It's overwhelming changing everything at once. Pick one thing and start with it. If time is your main concern, start with modifying your nutrition. Or start with exercising on the weekends.
I started by going to the gym with a friend 2-3 times a week. I had no idea what I was doing there, I ran a bit, a little core, then weights, then we'd go swimming. But it got me moving and got me started and, most motivationally, it got me results which only made me want to do more.
I feel like I'm just repeating what everyone else said now:
1) You have to REALLY want it.
2) Set a specific goal that will motivate you.
3) You may need to sacrifice other things.
4) Start small if it helps get you started.
5) The first 3-4 weeks are the hardest. Push through the lethargy.
6) Track your progress.