I don't understand!

There is loneliness, and no one wants to die alone.
People get married.
Even after marriage they feel the loneliness.
Happiness means 'to be happy even if you are alone'
And once you have learnt that, why would you want to marry?

If a relationship works out, you live together.
If it doesn't, you marry someone else, and fall in love with that someone.
What is love? I don't understand.
What is life? I don't understand.