I respect your opinion, and I understand that in your situation, it would be hard to think any differently. But God's word tells us that homosexuality is wrong. No amount of excuses, good intentions, arguments for it being 'normal', TV shows that advocate it as ok, books that tell us there is nothing wrong, etc, is going to change God's word. Either we accept God as the final authority, or we don't. If we say homosexuality is okay, then we make God out to be a liar, and we are touting OUR law and OUR feelings and OUR thoughts about what is right over God's law.
Yes, God will forgive people who are gay- IF they forsake sin and obey Him. But Jesus made it clear that if we continue to live in a sinful lifestyle, people who do this will not enter the kingdom of heaven. I'm sorry, but that's the way it is. We must let God be God. We may not like His rules. We may not think it's fair. We may think it's old fashioned. But God says it is wrong, and no amount of crying, tantrums and argument is going to change His mind.
Now, to answer your question- if gays want to marry, then let them marry. Those who are pagans are going to act like pagans, and it is not my job to tell them they have to act like Christians. Without the Holy Spirit, it is impossible for them to be any different. However, for Christians, it would be wrong for them to be gay and marry. If a Christian is gay, and wants to remain celibate, (and I know some), then I believe God is merciful and forgiving, and will help them deal with the urges they struggle with. But if he marries another gay and rebels against God by continuing to live in sin, well, then I would question his relationship to God. The fellowship would certainly be destroyed with God, because God cannot have fellowship with those who are in constant sin.
Edit: If you are straight, and you want to please God, I wouldn’t support gay rights, but I wouldn’t put them down either. You should continue to love those family members who are gay, but if you want to do what is right, you must choose to believe and obey God rather than man. We live in a society that is overwhelmingly being deceived by the enemy of God to believe that sin is okay. But it’s NOT okay. The path to life is narrow, and few are those who find it, Jesus tells us. It won’t be easy- because you will have opposition. But if God is for you, who can be against you?