"..As long as everyone in the relationship is consenting to it, then I have no problems..."

Exactly, my point is that polygamy is allowed, it is not compulsory.

However, homosexuality is not allowed by christianity as far as I know.

Also, I dont know whats the reason why many people have so much hatred towards polygamy (which is allowed by all religions and was common and was practised earlier) and on the contrary people find homosexuality acceptable (which was considered crime earlier).