This becomes an even more difficult question if there is someone else who holds the same values as you, you understand each other, and you get along really well; Is it worth settling for “second best”?
These questions are answered in one of the most boring—and yet one of the most insightful, and a times, interesting books ever written, Castle Warlock. (It was written in the 19th century by C.S. Lewis’ favourite author, George MacDonald. If you've never read anything by MacDonald you might enjoy the following. It's a children's story which shows how a man should respect the wishes of a woman. Little Daylight*)
Are you afraid of losing the one you love?
If you're afraid of losing the one you love you might find the following advice helpful.
Peterson’s advice (see video above) is not just good advice for couples; it is also good advice when dealing with a difficult parent. For example, if the way your father treats your mother upsets you, you might want to try thanking him anytime he does something for your mum (no matter how poorly, or halfhearted).
*This is an edited version. The full version can be found in MacDonald's book At the Back of the North Wind.