While I fully realize and understand that there are people who aren't monogamous or who don't like long term relationships, I'm not one of those people. While my first marriage at age 20 turned out to be an unhappy one, there were a lot of reasons for that, including that I was too young and naive to understand that we weren't very compatible. So, since we had no wealth, it was very easy to divorce after nine years. We probably would have ended it sooner but we had a child who was only 8 when we parted ways.
My current marriage has lasted almost forty years and we are still madly in love with each other. While my husband was a fantastic step dad, we decided not to have any children ourselves. We still have a fantastic sex life, which not everyone does at our age. I think of it like two dance partners that have learned the right steps and with each passing year the performance gets better. But, I do know people in sexless marriages that seem happy. Friendship is the most important thing in a successful marriage. We are best friends as well as lovers, so we have a lot going for us. We are both atheists, both dog lovers, both home bodies who no longer enjoy travel, both liberals politically, both New York Times and Washington Post junkies who love to discuss politics all day long. Plus, while my ex wasn't at all affectionate, my current husband is very affectionate, which is something that I love. We have so much in common that I can't imagine finding someone more compatible. We can argue without holding a grudge. Now that we are both retired, we spend most of our time together and we're never bored.
As far as married people sometimes having financial advantages, I look at it this way. Women usually make less money than men do in the work place, and since men usually die before their wives, why shouldn't the wife be given the husband's SS, if it's higher that her SS? Women usually are the primary caretakers of the children, even in this day and age. Some women give up their careers to raise children, as do a small percentage of men. Not everything in life is fair.
There are often societal benefits to being partnered. When I worked as a home health nurse, there were countless times when one spouse was taking care of the other one. While this was usually a woman taking care of a man, one of my favorite memories is of a man taking care of his totally dependent wife, who suffered from late term dementia. He fed her, bathed her, and talked lovingly to her. He married her when they were teenagers and her father threw her out of the house and he rescued her. They were poor country folks, but he never complained. We provided an aide three times a week to give him help with the bathing. If it were not for the things that older partners do for each other, a lot more of them would end up in nursing homes, usually paid for by Medicaid. Loneliness is very common among older single adults. Being partnered usually prevents loneliness.
Married people don't usually use as many resources as single people who live alone. For example, my neighbor is in her 70s, and is divorced. Her home is almost as large as our home, but she's probably using almost as much electricity and gas heat for her home as we do. I'm only mentioning this because I got the impression that some of you think that married people get a lot of special benefits. I think it all averages out, when you consider all of the things that partners do for each other, that often helps lower the cost of caring for the elderly or the disabled, since a loving partner will do the care without any financial gain.
Statistically people in long term marriages tend to be healthier, happier and have longer life expectancies. There are many positives about being married, but of course no one should ever feel as if they must marry. I just think that people should be honest with anyone they become romantically or sexually involved with. If you like having several partners, then tell each new partner that. We are all different, but we should all be honest with each other.
The only disadvantage for people like me is dealing with the death of a long term partner, or the possibility of being unable to care for my spouse if he should become disabled. But, life is full of sadness and disappointments, as well as joy and happiness, so the loss of a partner is just one more thing that the survivor will have to eventually face. We know that when we commit to a partner. And, sometimes, death of a partner is both sad as well as a relief since it's common for one partner to become dependent or confused while the other is still active and healthy. Some amazing people, like the man I mentioned earlier, cope well with these difficult situations, while others simply fall apart. Such is life.