Why Did He Do It?

There's something behind every story.
A reason. A motive.
Characters don't just act because they can.
No they do it for something or someone.

Soo lets set up the series of events.

New guy comes into town and gets a job where the girl MC is working.
A second job, apparently he already works in the mornings at other places.
Living in the city. And apparently single.
Plus he's very cute, very handsome.

But things don't add up.
As what the girl sees, isn't what everyone else around her sees.
He's handsome, that's obvious. So of course, she tries to find out if he's single.
From conversations she has with him, he states things in such a way to make her think he is. Plus he's being pretty flirtatious with her....
Only to have a coworker tell her he isn't single. He has a girlfriend. They're engaged. They're going to get married.

So she tries again, but he again makes it appear that he's single.
Until a work party where he brings in his girlfriend.

She had suspected as much, but was still a bit disappointed to find out that it was true.

Only to have him come up to her a week later and say that he's broken up with the girlfriend.
And seems to almost immediately show an interest in her. He hints that he wants to go out, but she puts him off. Timing was bad. She was busy.

Time passes.
Coworkers continue to talk. That he's lying to everyone, he's being rude. But she's doesn't really see that happening. They get along so well.

But then it comes out, he's lost his other job.
She finds out soon after that he's suddenly moving to a new apartment.

Then, when she and he finally find a time in their schedules to go out, he doesn't show.
And his excuse while plausible, seems rather flimsy.

Finally, one night he tells her, he's quitting the job she's at as well, and disappears, possibly never to be seen or heard from again.

Why would he do this?

For me, there are a couple of plausible actions as to why all this would take place.
One....his life is spiraling out of control. One thing going wrong set off a catalyst of other bad events that forced him to uproot his life and try out a new area.
What if the girlfriend spread horrible rumors about him.
What if the job he lost was because the company closed.
What if his apartment was infested with bugs.
What if he quit because of a different coworker.
What if he had a crazy roommate.
What if he has family problems happening.
What if he quit because of her?

Two...he's afraid of commitment, is rather flighty, hasn't yet found the 'one' to settle down with, that can keep his itching feet away from finding another new road.

Every Character has a motive.
Every Character has a catalyst that causes other events to happen to them.
Every Character has flaws that can cause them to be seen in the worst light.
Every Character has a redeeming factor that makes them seem like the best person in the world.

It's just up to the writer as to which problems and solutions match up so that the story that needs to be told can be told in the viewpoint that is best for what has been plotted out.

-Sarnic Dirchi