You may want to read up on lust, then....because that's actually what commonly occurs. It's not unusual for married men (married and attracted to women) to have their sex addiction escalate to the point of having sex with other men (not in a loving context, either)---purely lust. It's not the person they're attracted to (that's natural).....it's the sex....the pleasure...the high (which, I believe, is what makes it "unnatural" and not what God intended sex to be used as). The other person is merely a means to an end...and their humanity doesn't really matter. There's a verse: 2nd Timothy 3:4 that, IMO, applies to this.
The word translated 'lust' is a word that means desire, and in the New Testament, it is generally used in contexts that refer to illegitimate desire, desire that if acted on, would be sinful. The word for 'lust' shows up in the Greek LXX of the ten commandments in 'thou shalt not covet.' Paul wrote, "I would have not known lust if the law had not said 'thou shalt not covet.'"
I think you need to read up on lusts. Lusts isn't about the other person's humanity mattering or not. A pair of adulterers could care deeply about each other and each other's humanity. When David was with Bathsheba, he may have been very caring and gentle with her, not pressuring her to do anything she did not want to. He may have genuinely appreciated not only her beauty and her femininity, but also her personality and many different aspects of who she was as an individual. She may have admired him and cared deeply for him.
But she wasn't his wife. He'd coveted her and he'd committed adultery, physically, by sleeping with her, with the wife of one of his faithful knights who showed himself perhaps to be more committed to the army than David the king. Whether David was gentle and caring toward Bathsheba and respected her greatly as a person and had all the attitudes that a woman would desire in a husband, or if he was just using her for sex, either way, it was lust, and it was sin.
A woman in the news decided to marry her long lost father and move with him to New Jersey where adults practicing incest are not prosecuted. They may feel the same tender feelings for each other as a newly married couple. What man who is a decent human being does not love his daughter, want to sacrifice for her. And a daughter should love her father, too.
The question is, is it a legitimate desire to want to have sex with a partner in adultery or to want to marry and have sex with one's daughter or father? They may have the same emotions and attitudes toward one another that normal married couples may have. No matter what their feelings, their desires are lustful, because they are forbidden.
And neither of them measure up to the I Corinthians 13 kind of love, which does not delight in iniquity but rejoices in the truth. If they had this kind of love for each other, each would not want the other to sin against God. David would not want Bathsheba to sin. The daughter would not want her father to sin by committing incest and the daughter would not want his daughter to sin by committing incest.
'Love' that leaves God out of the equation is lacking. That's the problem with homosexuality. No matter how loving their feelings are for each other, it's not the kind of love we see in I Corinthians 13, which does not delight in iniquity. No matter if the feelings are like a normal opposite sex newly we couple who care deeply for one another, the right kind of love does not entice one's brother to stumble into sinning against God.
mkgal1, what would you say to the idea of two twin brothers who decided they were homosexual and wanted to marry one another. They couldn't produce children with each other, since neither of them produces eggs, so they don't have to worry about having children with genetic defects. Should these two be allowed to marry? Would you want your pastor or priest to perform the ceremony? Would you attend? Would you want to bake the cake?
