I have one answer for you.
It is not a nice, nor easy, answer.
That answer is: “You just do.”
How do you get motivated?
You just do.
How do you get inspired?
You just do.
I have such a platonic writercrush on this guy. People ask me all the time how I manage to write with a baby and a toddler and I mostly don't know how to answer it other than "I just do." I throw those kids into naptime and rush for my laptop and write like crazy until they wake up. After dinner, I write instead of watching TV (except for Vampire Diaries nights, which are sacred). It's actually not that hard for me anymore.
But here's the thing. I do it because I have to. I've gone and gotten myself hooked on writing and it feels bad when I don't do it. Even when I've got writer's block, it feels gross and horrible to sit around not writing. Maybe this is a positive side effect of having kids now. Maybe I don't know to be inactive anymore. But whatever it is, I'm taking it and running with it.
Here's my advice (not that you asked for it). Force yourself into a routine where you write at a set time every single day. It's going to suck for at least the first month or so, but once it sticks -- if it sticks -- you're going to get hooked. Just keep writing. That's all I can say.