Do we have to be social in life?
The Harvard study that studied groups of people for 80 odd years trying to find the sources of health and happiness found that:
The surprising finding is that our relationships and how happy we are in our relationships has a powerful influence on our health...
In addition, I remember reading in Daniel Levitin's book, The Organized Mind, that we all at least need 1 person who is a "witness" to our lives. This seems to be an evolutionary requirement for joy built into our brains.
So combining the two findings, if you want to be joyful, you need to at least have 1 deep, meaningful relationship that you're happy with. Given that people tend to get sick, die, move etc. it is better to have more people that you have meaningful relationships with, so that a setback here and there, like losing one's partner, doesn't render you completely lonely. Forming multiple deep relationships requires us to make the effort to find people who we can connect with, because there'll only be a small percentage of them who we'll form deep connections with.
So yes - I think continuously building new relationships, and investing in the one's you want to continue, is a good way to be healthy and happy.
Depends On Person To Person It Is Not Necessary Though One Can Be Happy Alone As Well :)