There is a saying that states, "opposites attract" but I don't know how accurate that is. It may be true when it relates to science, but is that really true when it comes to finding that lifelong partner?
In my opinion I think that a certain amount of compatibility is necessary when dealing with that special person you are bonding with. For instance, if I like the fine arts and he has never been to the ballet, that just may pose a problem. Actually the problem doesn't lie in the fact that he may have never been to the ballet, it becomes an issue when he has no interest in going to the ballet.
And what about long term goals? If he wants to move down south after retirement but you prefer the fast-paced city life, how do you compromise on that? To say that opposites attract is inaccurate in most cases. It's great to have different views and opinions about things, but if you cannot come to an agreement and are willing to compromise and step out of your comfort zone when it comes to certain things, then that may not be the right person for you.
When it comes to relationships commitment, understanding, compromise, respect and a genuine love for that person is necessary, very necessary.