Many people do have a need to be loved, you can't argue it away.

Most people have plenty of issues growing up, like low self-esteem, need for validation, etc. A combination of training, therapy, meditation, sense-of-purpose, etc can work wonders.

One such issue is nihilism, the kind you're showing here. Growing out of it often makes people happier, unlike growing out of love.

How about you worry about yourself and stop diagnosing people that choose to be with another person?

No one said anything about "needing." A person can have happiness and joy in their life while single, yet find another person who adds even more happiness and joy.