According to the Bible, marriage is a big deal. It's like the ultimate partnership, where two people become one flesh (Genesis 2:24) - talk about a permanent-roommate situation!
The Bible's also got some pretty high standards for husbands and wives. For example, husbands are supposed to love their wives like Christ loves the church (Ephesians 5:25), which is a pretty tall order. Meanwhile, wives are encouraged to submit to their husbands (Ephesians 5:22), but not in a Stepford-wife kind of way.
And then there's the whole adultery thing, which is basically a major no-no in the Bible. In fact, it's considered one of the Big Ten commandments (Exodus 20:17), right up there with not murdering anyone and not stealing their stuff.