It is possible to live a long and fulfilling life without a "partner." I'm glad we live in a society that is starting to realize marriage is not the objective of life. Treating people kindly, interacting, making positive contributions to society, growing and maturing-these are all important and do not require a "partner" to achieve.
I do, and I'm 50 years old. I've never been married or had a "partner" in any sense of the word. It's not that I'm not interested in finding that man with whom I could spend the rest of my life. I've just never actively pursued a relationship. I think I've done very well. I have family and friends, so I'm not lonely. If I didn't have family, I might feel differently.
I think that people can live without a partner in their lives. Some people choose to live a lifestyle like this for many reasons. For example, they may not want an emotional connection with anyone or they may not want any kind of commitment.
I agree with both of the above posts, although partner doesn't necessarily mean husband or wife by law. I myself am in a committed relationship of 4 years and have no intention of getting married. However, I definitely don't want to live without my partner! But, if I had to, I could. So do we draw a line between people who choose to live without a partner altogether, and those who may lose a partner and then choose not to take another? I suppose, in either case, confidence and a strong sense of self apply. And as poster #2 pointed out, financial difficulties should be taken into consideration. One would also need financial independence to live without a partner.
Obviously there's no real answer to this question. You're asking for numbers, and this is something which just isn't quantifiable. If, however, you're wondering what kind of person can live without a partner, there are some qualities which are identifiable. Obviously independence is necessary, as are strength of will and a kind of self-sufficiency. If one can be content in any circumstance, one can certainly be partner-less. I guess I'd think of it this way--there are a lot worse things in life than not having a partner.
If by partner you mean a husband or wife, than a lot of people can. Actually, the rate at which people stay unmarried throughout their lives is slowly rising, and people in the US and Europe are waiting longer to get married. So it is very possible to live without a "partner" for much of a person's life. It's just that most people don't want to, and the vast majority of humans decide they want to be married in their lifetime.
It's also true that in some countries and societies, it is difficult to survive on one income, especially for women in places like Somalia or Afghanistan.