I agree and disagree. I don't support gay marriage, because I'm a Christian. But, God told us to love "everyone". We are not to Judge. But we are to be "discerning". Which means we are to be wary of others sins. But, did you know that to God one sin is no worse than another? Let's say I drink too much (just a hypothetical! lol!)...which is a sin. He never said not to drink, but don't be a drunkard. Being a drunkard is a sin. But to God, being a drunkard, or being gay, are sins that are equal. Robbing people is no more a sin than murdering someone. These are all equal to God. God said "hate the sin, but love the sinner".
I guess if I was in that situation, and if the gay couple were really close friends, I would have to let them know I'm uncomfortable with it. If they are good friends, they should understand. If not, then you should ask them to leave. You shouldn't be expected to accept a situation that makes you uncomfortable in your own home.