It is not marriage if it is not between a man and woman who are both free to marry each other. What’s next? Marry your beloved pet?
As to eiver min hachai – it may not be exactly the same, but even if I were not Jewish, I could never eat lobster after seeing a cooking show demonstrate how they cook LIVE lobsters by throwing them into boiling water. Anyone who thinks that is not cruel, is in serious need of cashing a reality check.