I see nothing whatsoever to back up that assertion other than your own suspicion.
My
suspicion is my reason for not supporting gay marriages.
Why on earth would I want to be leaglly married to my room mate?
Because he has health insurrance and you don't and it'd be cheaper, for both of you, to add you to his plan, through marriage, than for you to get your own plan.
what if we fell out would he get half my possesions? what If I began seeing a girl? could he divorce me for adultery and take all my possessions?
You could have a pre-nup.
"marriages of convenience" occur in with hetero couples, there is no reason whatsoever to think it would be any more or less likely with same sex couples.
I think they would be more likely because, personally, I would enter a "marriage of convenience" with a man before I would with a women, all sexualities aside. Personal reasons aren't evidence that it
will happen but they are reason enough to not support something.