Finding a Good Reason
Years ago I was reading a How To book on writing and I came across an excellent lesson on character motivation and believable plotting. It had to do with the plot's crucible. In a nutshell, a plot crucible is the reason why characters must continue toiling away, staying together, and not fleeing or simply saying, "Screw this, I'm outta here."
It was a revelation for me and has helped me plot every single book since then. Sometimes I read a novel and I think, Why doesn't she ask him if that woman is his girlfriend? Or I will wonder, Why are they staying together if they're both so miserable right now? There has to be a good, sound reason for people to remain shackled to a situation or premise or idea. If not, they just look stupid.
In real life we all have a fight or flight response. Flight is easiest. Things become too messy, too dramatic, too stressful, and we take a powder. Easy. Fight is much more difficult and usually we resort to fighting when we feel we can't run away. Something is holding us in place. Running away would cost us too dearly.
For example, in the first question above, why the heroine doesn't ask a simple question of the hero to clear up a huge misunderstanding. This is a weak plot device and most readers will roll their eyes and think the heroine is as dumb as a stump or -- worse! -- a doormat. If she goes around upset because she believes another woman owns the hero's heart, but can't bring herself to ask him about it outright, can we really admire her and want to be like her?
The crucible here is nonexistent. There is no good reason why she is hanging around. Now, if the other woman told her that the hero is betrothed to her and that her family is depending on the marriage (and the hero's money) to save them from being thrown out in the street as paupers and that the woman's father is gravely ill, this might give the heroine pause to think that she should step back and not become the reason a family is tossed out of their home and responsible for an old man's death. But then you have to find a good reason why she wouldn't discuss this with the hero. I mean, wouldn't it be logical for her to ask him about it? So, then you have to decide how he's going to answer and how this will either strengthen or weaken the crucible. See? Sometimes you have to just abandon a plot or plot line and start all over.
But that, my friends, is plotting.
So, when I plot, the first order of business is the crucible -- the trap from which the protagonists can't escape because escape would be far worse than sticking it out. It has to be a solid trap -- not some flimsy thing that wouldn't hold a butterfly prisoner. Sometimes, it's a fight over a place (land, house, business) and sometimes it's a fight for a person (a child, a parent, a first love), and sometimes it's a fight for a thing (inheritance, honor, revenge). Whatever the focus, it must be clear and sharp and the reader must buy into it totally. If they pause to wonder why the protagonist doesn't just throw in the towel and be done with it, you've lost your battle and your war.
When you have a crucible that is a fortress from which your characters dare not leave, you have a formidable plot and iron-clad character motivation.