But, the pop star added, he will feel sorry for the many gay couples who live in countries that prohibit such unions.
"It has been a long struggle for equal rights to gay people in Britain, but now, in the 21st century, we have real civil rights, tolerance and final acceptance in our lives," John wrote in The Observer, a Sunday newspaper.
"Next Wednesday, on the happiest day of my life, when I celebrate a civil partnership with David, I will be thinking, however, about those less fortunate than we are. In many countries, having a same-sex partner is still outlawed."
Quoting Amnesty International, John said an estimated 80 countries still have laws that criminalize adult same-sex relations. He also cited specific cases of abuse in countries such as the United Arab Emirates, Jamaica, Uganda, Iraq and Poland.
"Throughout history, gay people such as myself and David have often been made scapegoats by those who fear that we are a threat to the status quo," John said.
More than 600 same-sex couples plan to form civil partnerships in England and Wales on Wednesday, the first day that such ceremonies become possible. In order to get the law passed that allow such unions, the British government avoided potential opposition by avoiding the term "marriage."