Love is a bunch of neurotransmitters and hormones - it exists in order to carry on the species through sex. When the chemicals go, its often the children and the house that keep couples together. For some people the chemicals and the psychological needs carry on. For many it does not ! I wish I could love somebody - but it has never happened (unrequited love yes!) I wish all couples could stay together but many do not. Perhaps the mormons or muslims have got it right, multiple partners!
Marriage is a terrible idea. Not only it is unnecessary commercialized private show to needlessly display overly naive promises that defy human nature, but also domestication of one another effectively destroys all affection.
"Until death do us part" is naive promise that stems from people insecurities. Sin shaming and capitalist propaganda has left most people unsatisfied with themselves, things they use, life they live and partners they have, thus leaving people fearing to stay alone, fearing their desires and fantasies. Giving naive promise does not magically free people from lust and desire, but instead limitations cultivate hate and sense of discomfort in limited freedom.
Marriage refuses marital relationships of same sex couples and polygamous unions, which in no-way is business of church, the state, company or third party individuals.
Passion and affection is the need of a partnership and of fear that other party can cease relationships at any moment. By marriage people get false sense of security over other partner.
In the sense of commitment, marriage will always be viable. But in the legal sense it is not. When there are children to be provided for, then the legality needs to be there to establish the terms in case of separation. But barring that, no one should enter into a legal contract that puts all their worldly goods up for grabs if there is a separation.
it is because of questions like this the divorce rate is so high. People think it is outdated and just do it to do it. It is not outdated. It is a way to show that you love someone until the end and no mater what you are committed to that person. It legally binds you together as one with your mate.