Right Reverend Nicholas Chamberlain, the Bishop of Grantham, said he was moved to speak out about his sexuality after a British newspaper threatened to expose his personal relationship.
"It was not my decision to make a big thing about coming out," he told'The Guardian'.
"People know I'm gay, but it's not the first thing I'd say to anyone. Sexuality is part of who I am, but it's my ministry that I want to focus on."
Under Church of England guidelines gay bishops must remain celibate and are not permitted to marry.
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The church says that it supports clergy in same-sex civil partnerships, but marriage is a union of a man and a woman.
The Bishop said he had been with his partner for many years and that the relationship "is faithful and loving".
"We are like-minded, we enjoy each other's company and we share each other's life," he added.
"I really hope I'll be able to help us move on beyond matters of sexuality. It's not to say this isn't an important matter - I'm not brushing it aside," he said.
The Archbishop added: "His appointment as Bishop of Grantham was made on the basis of his skills and calling to serve the Church in the Diocese of Lincoln.
"He lives within the Bishops' guidelines and his sexuality is completely irrelevant to his office."
A Church of England spokesperson said: "Nicholas has not misled anyone and has been open and truthful if asked. The matter is not secret, although it is private as is the case with all partnerships/relationships."