45 and Holding by Jacki James

Empty Nest meets Mid-life Crisis
When widower Scott Anderson’s daughter goes off to college, he finds himself alone for the first time in as long as he can remember. With his primary role no longer being “Claire’s dad,” he realizes he isn’t sure who he is or what he wants out of life.

For Craig Baker, a mid-life crisis crept up on him in the form of restlessness that a new Jeep didn’t solve. Just as he’s contemplating getting a tattoo to try and shake himself out of this funk, he meets an old classmate who is in the same boat.

They’re both trying to figure out who they are at the age of forty-five.
For one man, there’s a slow realization that maybe he doesn’t need something to cure the restlessness, but someone.
For the other man, it’s the discovery of a new side to himself and the willingness to embrace it.
And for both of them, it’s realizing that mid-life means you still have half your life left so you might as well live it.