There's MORE than 1 person for everyone... :p! Some just will make you feel more complete than others i suppose... but you can definitely be compatible with more than one person. :]!
Does that mean that everyone finds someone to be with? Definitely not!! because sometimes even if we are compatible with many, we just don't put ourselves out there to be noticed or simply walking in different paths... but that doesn't mean that there wasn't someone out there that could be happy with you... There's plenty!