You are writing about a person. You are describing his qualities, perhaps his business acumen or homemaking fervor or social charm or brilliance as a surgeon. You add, then, he "happens to be gay". Why did you add that information? If he "happens" to be homosexual, then it is incidental to the description you were making; the information is irrelevant and shouldn't be included. You probably mentioned the fact of his sexual orientation as a quiet compliment to you, rather than to him, in praise of your own tolerance; but in doing so, you diminish your qualifications of character to praise of him.