The Myth of The 50/50 Relationship
Let's talk math.
1 +1=2
10 /2=5
50% of 100= 50

The truth of the matter is that no relationship is 50/50 because one person will always contribute more to the run of the relationship that the other. For example, in the 21st century many woman have full-time careers outside of the home and because of the way the economy is many men have lost their jobs becoming stay at home dads. There is nothing wrong with that, but here is where the math come in.
The woman is already contributing 50% by just going to work but let's factor in when she gets home she still has to deal with the kids (10%), housework that only she can handle (5%) and spousal time (10%) now she is up to 75% and he is at 65%. This equation also works when the man works and the woman stays at home.
In cases where both parties work outside of the home they start out at an equal 50% each but someone has to cook dinner (10%), walk Spot (10%), help with homework (20%), clean (10%) and the list goes on and on leaving the scale slightly unbalanced.
Don't freak out yet! There is nothing wrong with your relationship is slightly unbalanced (note that I put emphasis on the word slightly) that does not mean that your relationship is doomed. It is possible to have balance in an unbalanced relationship. I know that sounds strange but hear me out. I am a believer of each person in the relationship using his or her strengths to help make the relationship stronger and to help the family run smoother. For example if she is a wiz at getting the kids in and out the shower in less than 30 minutes while he is a master in the kitchen then utilize those strengths to the best of your ability. If he keeps the house tidy while she is better at handspring the household finances then so be it.

The only time that this equation does not work is when the scales have been tipped too far on one side. That is when you find your equation more 80/20 or 90/10 and one party is taking on allot the entirety of the relationship and of the household. When you find yourself in this predicament you need to speak with your partner to find a suitable solution to the problem.
I'm all for equality in a relationship but do not strive too hard for things to be 50/50 because not all of the time does the math have to add up.
TTYL