You worded the thread title badly @IStoppedBelieving
Of course LOVE is a thing. I LOVE my cat, and she makes me so happy every time I see her, I LOVE my daughter and would die for her, I LOVE my parents, and there's nothing I wouldn't do for them. I LOVE my DH although I want to slap him across the ass with a wet cod sometimes as he can be an annoying twat. (So can I!) Overall though, I enjoy my life with DH, and do love him, and he loves me, and we take care of each other.
I know what you mean about romantic love though. I don't think it's there for many. I know quite a few women in real life who have been with their husband 30-40 years - and they say that not only are they not in love with him, but that they never have been.
I come from a working class background, and many women in my world, got married in the 1980s to their boyfriend of 1-3 years, in a time when as long as a man has his own hair and teeth, and a job, he would do. ANYthing was better (for them) than staying single.
Many girls dated lads whilst in their teens, (or very early 20s,) and were engaged, married and pregnant within 2 years of meeting him. Many of these women are still with these men, after 30-40 years, and don't really love him, and never have. They have had several affairs between them in the distant past, and an awful lot of rows in the past too, (and a few recent ones,) and don't have loads in common.
But the marriage isn't awful, and they do their own thing, and sometimes do stuff together, and are better off together financially. Finances and poverty keeps people together, a lot more than LOVE does.
They have stayed together, because it's better than being alone. (For them.) The working class girls who stayed single, ended up staying with their parents until they were middle aged, and then had to fight for the tenancy of the council house they grew up in. Many lost that fight, and ended up in a private-let flat , fighting for extra hours at work, just so they can survive.
Being single may be OK for some, but it's a miserable life for many. Basically, it's a miserable life if you're quite poor. It's a much better/easier life if you are with someone. And if you and your partner rub along OK from day to day, and your are not deeply in love but still like and care about each other, and you are OK financially, and quite comfortable, and you live in a nice house in a nice area, then why change things? Why leave?
Also, many women stayed for the children, (whilst they were young) and then stayed while they were at college and then uni maybe, and stayed until the youngest one left. And then it was too late to leave and start over.
And I'm sorry but despite some posters saying that they, and LOADS of women they know left their husband after 30-40 years - at the age of 55-60, and found a wonderful new man, retrained for a new fantastic career, and now have a lovely 2 million pound apartment overlooking the River Thames; the reality for most women 55+ who try to go it alone, is that they will end up in penury. Scraping pennies together for food, and begging their workplace for extra hours, and having to claim benefits to be able to survive.
No, don't mock or dismiss my words. That is what it's like for many women. Not all women live in the parallel world of mumsnet where shiny new careers, lovely apartments, amazing new friends, and wonderful rich sexy men fall into our lap if we leave our husband of 30-40 years to try to 'start over.'
So yep, going back to the thread subject. The OP is right that many people are not really in love. Some may have been to begin with, but when the reality of life, housework, children, having to tolerate your husband's shitty in-laws and annoying friends, having to do 90% of the housework and childcare (whilst your DH focuses on his big MAN-JOB and hobbies,) and having to work a job you hate (to make ends meet,) the shine wears off for many women...