Well, if this guy "acted" straight and had sex with a woman and pro-created, then he ain't THAT gay after all. jmo
Did you read his letter out of curiosity?
If you did, you'd remember that he acted straight because he was raised to believe that homosexuality was wrong in the eyes of God; it's unacceptable in Christian culture. He claims to love the Lord and so he thought that by being married and having a family he would "be fixed". Sadly, he isn't unique in this as I've known quite a few Christians who had homosexual desires do the same thing.
The man having children is virtually irrelevant to his sexual orientation. The most unattractive woman could cause a physiological reaction to a man... it doesn't mean the man is sexually attracted to her. This is even more understandable as he loves her, just not as a husband ought to love his wife. He went through the motions without actually having any heterosexual desires... He thought they would come as a result of his perseverance.
However, he gave up fighting sin and will be divorcing his wife... This is his error, not his homosexual desires that he forsaked.