In most cases, especially in relationships, you will only get 80% of what you NEED and you will hardly get the other 20% that you WANT in your relationship. There is always another person (man or women) that you will meet and that will offer you the other 20% which is lacking in your relationship that you WANT. And believe me, 20% looks really good when you are not getting it at all in your current relationship. The problem is that you will always be tempted to leave that good 80% that you know you have, thinking that you will get something better with the other 20% that you WANT.
But as reality has proven, in most cases, you will always end up with having the 20% that you WANT and loosing the 80% that you really NEED and that you already had. Be careful in deciding what you WANT and what you NEED.