If I may suggest something that helped me: Find a program, do a program, find a new program. http://www.bodybuilding.com/fun/find-a-plan.html Nobody can stay motivated doing the same thing forever. I recently ended an 8-week training program targeting strength and mass, then froze my membership and started running and am working my way into a steady calisthenic program (bodyweight exercises, easily done outdoor with a pull-up bar and other jungle gym stuff). Diversify and keep your original goal ever everything-- for me, its meeting West Point physical exam requirements, and having confidence in my strength. How I do it is therefore flexible. Those apps ain't gonna work for you, they're for you to look back on and be proud that you worked, that's it. If you mainly run and are losing motivation, fighting time constraints etc. but don't want to find something different, change up your run. As in, change up how you're running, short distances or interval training etc.
I love bodyweight exercises and highly encourage people to pick them up. Bodyweight exercises have just about the lowest barrier to entry in terms of working out - you don't need any equipment, you don't need to leave your house, you barely have to change out of your business clothes if you work during the day. Heck you can sneak some in at work if you choose some subtle ones. For those of you that use things with apps, there is one called "You Are Your Own Gym" by Mark Lauren. It does cost money (I may have gotten it for free on a special one day, can't remember) but it provides an extensive library of bodyweight exercises (GUYS DID YOU KNOW THE CRABWALK IS A BODYWEIGHT EXERCISE?) as well as programs and steps to help you achieve certain milestones - for instance, if you want to be able to complete a pull-up. It has videos as well as descriptions of the exercises. I'm also big on incorporating fitness into daily life. I walk the stairs at work when I can, sometimes instead of using a bathroom on my floor I walk up or down a flight and then use the bathroom for example.
Important thing to note is how hard it can get. If you've been hitting the gym for a while sure you might knock out some push-ups or a good plank, but how about a set of muscle ups? A human flag? There's a lot of room for progress. Also your body burns fat way better and the muscle it builds, on most guys at least, is insane.