One interesting detail that I've noticed when I was doing my MLT project was that the Patriarchs had a very difficult love life.
Abraham married his step-sister, which resulted in them not being able to have children. Also, once Isaac was born, Sarah became competitive of Abraham's other wives, which added to the difficulty of their relationship and resulted in exile of Ishmael.
Jacob married sisters, which also resulted in a difficult relationship. His wives competed and fought with one another so I am sure it was difficult for Jacob to manage that. From Jacob's story we see that his wives competed almost through the entire life, especially so when they were bearing children for Jacob.
Joseph had to marry an Egyptian woman. And even though Torah is silent about their relationship, it was also probably rocky due to the differences in cultures and the issue of the Torah observance.
Even Moses had difficult relationship with his Midianite wife, whom he had to divorce once he had taken over the leadership of the Hebrews.
The only person who had more or less good relationship with his wife was Isaac, but as you know his children fought with each other, so his family life was difficult as well.
What does this all teaches us? Well...life is a terrible thing no matter who you are and where you come from. Even our Patriarchs had their share of problems. Therefore, never envy someone else's wife because you do not know what kind of crap they had to deal with in their relationship. Usually it is just as bad, so you would not gain anything by adultery. And of'course remember to humbly accept your woman for who she is because frankly - it could have been much worse :p