Seems very stingy to hold all your love in your heart without giving it to anyone. That is assuming there is love there.
I seek out friends and partners because I have a lot of love to give. Find love in your heart to give. If there is none there and you are happy alone, I find this very sad.
I think it is very rude to suggest that lonely people are immature. Where is the compassion and empathy?
That is just my opinion though. If I cannot share my life, what is the point. Just an endless self serving, self absorbed existence.