A marriage is a contract. If one party wishes to change the terms of the contract then either the other party agrees, or the contract is voided.
And it is a change of terms. Statutory grounds for divorce of a mixed-sex couple include adultery. A same-sex couple does not have adultery as grounds for divorce.
Trans activists are demanding rights that no one else has:
- The ability to enter spaces designated for the opposite sex unchallenged.
- The ability to unilaterally change the terms of marriage contracts.
- The ability to compel speech of others in the form of pronouns and compelled lying about sex class membership.
- The ability to erase and rewrite their past, even when doing so adversely affects others.
No marginalised group in history has ever wanted more rights than anyone else like this. Which tells you that the trans activists who are doing the shouting are not actually marginalised.