I like a lot of this article, but I would wager Mr. Gottman's salary that if you ask long-term happy marriages (i.e. couples who both self-identify as happy and have been togther 20 years or more) they would definitely say that happy marriages are about 50-50 transactions*** if you add the caveat that both partners are looking at a lifetime together and a life time of give and take.

If you are looking at having a constant balance (eg. "I took out the trash this week = I get a blow job on Saturday") then that IS transactional ("keeping score") and will not lead to happiness because life doesn't work that way. Thus the traditional wedding vow of "for better or worse, for richer or poorer, in sickness and in health." There are going to be times when one partner can't do X for a period of time when they did it before. In a long-term partnership, you work through that.

By definition, if you feel you are not in a 50-50 relationship, then you are by definition not in a partnership. What someone needs to be happy varies from person to person. If after years together one of the pair feels that they are not in a 50:50 relationship, they are not going to be happy.