Ultimately, your 'soulmate' is not the one who 'completes' you -- they are the one who 'compliments' you...
They are the one who will share many of the same likes/dislikes you may have, but will have just enough differences to compliment your personality...so it is ok to share the same desires, vices, likes, dislikes, faults, etc., as long as they are not ultimately destructive...
This is when the ability to anticipate your loved one's needs is at its best. It becomes an instinctive thing rather than a 'trying to please' thing...You will find yourself doing things simply motivated by the fact that you know what your partner's reaction will be, and most of the time you will not even realize you are doing it...
You will never be so angry at someone, but at the same time so anxious to resolve the issue to get back to the level of comfort that you share with the one who 'compliments' you.
We often tend to hate in others what we hate in ourselves...For example, I hate procrastinators, yet at times find my myself procrastinating with the best of them...lol
BUT! That being said, I can accept that in myself, (although I may seriously dislike myself at times for it!) and as such find a way to look past it in others to the person beyond their faults...
Love, honest love, requires Empathy. It is a sharing - of joy, of pain, of laughter, of tears. It make's one's soul a reflection of the partner's moods., and as a room seems larger when it is lined with mirrors, so do the joys, and pains, become amplified.
But...the beauty of love, whether in passion or friendship, is that the 'sharing' multiplies the joys and thins the pains.
This 'empathy' gives us purpose...
Without purpose, we find no satisfaction.
Without satisfaction, we find no contentment, and without contentment, we find no joy...