[Not SpaceGhost]

One word:

Temptation.

[Kaylah]

Some people get married way too soon, when they are young and don't know what they are doing. Honestly, I don't know if I believe in marriage, so I may never get married, but if I do, I would wait until I have been in the relationship for several years and am really sure about it.

[daimashin]

In my opinion, it is because of immature marriage. People don't really know each other very well and rush to get married. Couples don't really know how their other half is like, and without thinking it through agree to marriage just because they want to. Most of them never took into consideration what it would be like to live with someone that isn't related to you by blood.

[warmweatherwoman]

I have a slightly different take on your question...I truly believe the human species just was not meant to be monogamous...perfect example..the divorce rate when infidelity is involved. Someone made a comparison above about marriage being like eating pizza for dinner every night of your life, as funny as that sounds...its has so much truth to it. People need and want variety. We change and grow every day, week, month, and year. Nothing ever stays the same...our jobs, our community, our relationships whether friendships or romantic...everything is temporary- even your emotions.

[Mod Mark]

I've heard many times that after a couple have been married after a certain time, communication starts to lack, so I don't know if that could be the reason.

[Otaku]

Some people aren't truly ready for the commitment, some people are way too young, money problems, if they have a child they might not have enough to support the family, etc.

As for if they were a some what older couple, maybe the two didn't agree on things.