You're so right .... Being gay is not s sin ... Just like being straight is not a sin .... If a gay person decides to have a sexual relatioship with another ... Then it is a sin ... just as it is a sin for a single heterosexual person to have a sexual relationship. Then again we do know that the heterosexual can eventually get married and change their Lifestyles. Sadly this is not a solution for the homosexual person who may not be happy with someone from the opposite sex.
Can a person live without sex? Yes ... Priests, Monks and Nuns have to and many others who have chosen this state. Of course they have taken themselves away from the world in many ways and totally trust in God ... What does Jesus say about this? In the following verse Jesus is speaking about those men and women who would decide on chasity in order to live for Jesus.
"..... there are eunuchs, who have made themselves eunuchs for the kingdom of heaven ...."
So if, after seeking help the homosexual person's needs are still unchanged then all I think is left is the advice Jesus gave, and which He faithfully followed, living a chaste life and Offering it all up to God.