Freddie locks horns with Helen:
...many people see marriage, as Helen does, as bound up in child-rearing and traditional gender norms. The problem is that many people, straight or gay, don't particularly give a shit about child-rearing or traditional gender norms, thanks, and will be subverting them anyway. The difference is that the straight couple gets to subvert them from inside marriage and the gay couple doesn't. This is yet another example of a situation where cultural conservatives are trying to use form and rules to fight a battle that was won in psychology and culture long ago.
Respect for traditional gender roles and traditional notions of marriage can't be enforced; you can calcify the institution and draw the boundaries so that you're excluding gay people who might undermine them, but the straights inside are doing a very fine job of undermining all on their own. Conservatives love to say that government can't do everything, and they're right. One of the things government can't do is force people to respect norms and codes that they don't want to.
Look, I'm on record as being a passionate defender of both marriage and romantic love. I wish more people would live out the philosophical tenets implied in their marriage oaths. But those things can't be enforced, and never could be, not by law, morality or religion. Only the individual respect for fidelity and individual love for one's partner can create the kinds of attitudes I want people to show towards their marriages, and I find respect for fidelity and love for one's partner to be attributes shared by both some straight and some gay people.