I don’t think that someone who has homosexual desires would necessarily be able change those desires on becoming Christian. Basically one may become a Christian and still feel those same desires and temptations. Consider also that the greedy are mentioned in this list as well. We all struggle with sin and temptations. Salvation depends on the Lord Jesus and his power to keep his people. It isn’t lost if one were to fall into sin even if frequently falling for the same temptations over and over.
Homosexuality is a desire that is rooted in the flesh and participation in it is based in drinking the toilet water that this world has to offer.
Jesus said, that if you drink this water you will thirst again; but if you drink the water that He can give, you will never thirst again.
As soon as sex is no longer the issue, someone who was previously homosexual can enter into a loving relationship with someone of the opposite sex.
In my own marriage, sex is not an issue. We come together about once every two weeks for the sake of intimacy; however neither one of us feels that concupiscence (being able to bring the partner to the point of climax) is the point of our sexual union.
I believe that in homosexuality, it is the ability to bring the other person to a place of intense pleasure that is the issue. That is why they want to have sex with someone of the same sex; because they feel that they know better how to please their partner since they have the same organs and therefore know what buttons to push.
Again, when sex is no longer the issue, someone who previously felt that they could only be compatible with someone of the same sex can indeed cross over into a heterosexual relationship and even be fulfilled in it.