No 3 reason: Expectations. Damn expectations. Mostly on the part of women, fairy tales
expectations of being saved by the prince charming and being happy ever after. Yes,
WOMEN BELIEVE THAT CRAP because they are conditioned to believe it from early childhood.

#3 is the most daunting for women

Although somewhat tongue-in-cheek, there's actually a lot of truth in the following -

Men marry women in the hope that they won't change, but they do
Women marry men in the hope that they will change, but they don't

Then of course, there's the unanswerable question - If all brides are beautiful, where do ugly wives come from? lol

Why do husbands often die before their wives? Because they want to......

To be honest, I'm truly envious of my parents. They've been married for over 60 years.