Since arranged marriages aren't as prevalent as they used to be, the reasons why we might be together with someone we don't really love generally fall into several different categories. Let's walk through some of them.
This might be one of the main reasons people might get married. Money often equates to security, because it can provide a nice home, a comfortable life, and provide for emergencies and the future. Financial security, however, doesn't always equate to happiness, and if love is not a part of the equation, it can still allow for discontent.
There may still be reasons in this day and age where being married is better than just living together. In the past, taxes for married couples have been higher than head of household or other possibilities (though much has changed in the last few years). People still feel pressure to get married by family or friends and might end up doing it just to avoid being told. Not a very smart idea, obviously.
I'm not sure how frequent this happens, but sometimes the feelings that one has to another person isn't so much love as it is a desire to care for someone else. I suppose it's possible that it can turn into love, as service and sacrifice are among the highest forms, but pity or feeling sorry for someone else generally doesn't last a lifetime. The same can be said for a sense of duty or obligation.
This can happen if one or the other, particularly if one or the other in the relationship is dominant or violent. The other person might get married because they don't want to upset or cause the one prone to violence to act out. Unfortunately, someone who might need some anger management, or is actually sociopathic, doesn't need to be provoked. They can find their own mostly trivial reasons to fly off the handle.
How much this happens, who knows, but there are still ambitious and opportunistic people in this world, and if they have goals they can't otherwise reach, marriage is a possibility. Especially if it proves mutually beneficial. Regardless, it's not love or necessarily having and raising a family one is seeking, but the need to have greater control over events and people. This might happen more amongst corporate or governmental types, or gangs and organized crime.
* THOUGHT IT WAS LOVE
Love is not an exact science. Sometimes we think we're in love, when we're really not. It generally takes more than a chance meeting or some other short fling in order to know. And love generally grows into its own over time. However, the exact opposite can happen too, as a couple's interests and priorities change and move farther apart. It's not so much love never existed, or couldn't continue. People's needs can change, but they can also be inattentive.
Marriage takes communication, nurturing, kindness, patience and love on a consistent basis. Absent those things, a marriage tends to fall apart.
I think these are some of the reasons why people get get married, but not necessarily be in love. There's probably others, and it happens more than it should.
We need to realize the fact that we can't come to this world alone without meeting or interacting with people. It's never possible if animals interact with each other, then how can humans just decide to stay single or alone without talking with anyone or making friends or making family before such person leaves the world.
The main reason why we are now with people whom we are not in adoration with before is due to the presence of love. Love is something that has to be shared amongst every individual and naturally we tend to love each other due to the law of nature. This is why you may actually fall in love with someone you haven't met before in your life because you actually loved that person due to some reasons or the other. It's just like a mutual feeling that is meant to exist between people.
The astonishing fact about this is that we tend to be happy and secured when we are with our loved ones even though we didn't know them before and we now feel happy after meeting with them. This is just the law or nature and we can never go against the rule of nature.
Lastly, we also tend to like those who may seem good to us in terms of their character or behavior. Just like we may be attached to some nice people because of their caring nature towards us. The love tend to keep increasing without any doubt due to their caring nature towards us.
Thanks for reading and I hope this helps.