This is an issue I've been asked about several times, and even ran into myself. My fiance is not learning Japanese at the moment (though hopefully in the future she will want to once I'm fluent :) ), so sometimes it makes studying difficult. It's not anyone's fault, really, but studying a foreign language does not allow one to easily communicate with their better half. The same is true at work. Nobody there knows/speaks Japanese either.
So, how do I fit studying Japanese into my life?
The answer is more simple than you would think. It's a concept called "weaving", where you mix it in along with what you are currently doing. I'll start with the job.
I work at a job that does not require constant (verbal) communication with others, so I can squeeze things in. Typically this is in the form of listening to Japanese radio or music, or having anime play in the background (though for listening only, not watching because then I wouldn't get anything done!). I also use headphones so my co-workers don't have to listen to it. It actually allows me to concentrate more on my work because I don't hear conversations outside of the headphones, which can be very distracting. Added bonus!
I also listen to Japanese and try to follow along if I recognize a word, sentence or phrase as I drive to or from work. Why waste the 30 minutes, right? On my lunch break, I study and/or review Kanji. That's easily 8+ hours a day of Japanese exposure - all while handling the other tasks at in front of me! And that's just at work.
At home, I do things a bit differently. I'll listen to Japanese music/radio while I walk the dog, or while I mow the lawn. Any time I'm on the computer (which is all in Japanese), that's more exposure. I hit Japanese web sites only, and play Japanese games when possible. I also try to review a few kanji before bed, which helps them stick.
Admittedly, I don't do as much Japanese when my fiancee is around because it just doesn't work most of the time. But when she's off doing something on her own, I flip on the Japanese. As long as I touch the subject a few times throughout the day at a minimum, I'm okay with that.
My point is this - it doesn't matter how busy you think you are, there's always a way to squeeze in Japanese somehow. So instead of going on about how you don't have the time, just weave it in and you'll be there before you know it.