I doubt the examples he mentioned can be reduced to simplistic economic theories.

For the movie for instance people could stick on hoping things will get better and things could.

For relationships most are loaded with emotions that make us irrational and decisions to make or break would also involve a multitude of other factors well beyond the scope of economic theories of sunk costs and self interest.

Listen but make your own decisions. You learn by listening to yourself, making your own mistakes and taking responsibility for them.