The first thing my family has taught me is that you should make sure that when you want to marry someone, you know you can last til death as you say in your vows because having kids through a divorce is so unfair to them. The kids blame themselves and view parents differently, plus throw in sports and school and living in two homes, it can be stressful.
The second thing my family has taught me is jealousy gets you no where other than gaining hatred or making comments that are unnecessary. For example if one side of a family has more money than the other one side will get mad of the others things and make conflict.