My Lords, I, too, cannot support this amendment. Under existing law, if a married man has a sexual relationship with another man his wife cannot sue for divorce on the ground of adultery. She can sue for divorce on the ground of unreasonable behaviour, based on sexual infidelity. As I understand it, the Bill adopts the same approach in relation to same-sex marriage and sexual infidelity with another same-sex partner. This seems to be consistent with existing legal principle. It involves no detriment whatever to the other party to the marriage, who can obtain a divorce on the basis of unreasonable behaviour. I, too, am concerned about the uncertainty inherent in the noble and learned Baroness’s amendment. What is,
“a sexual act … similar to adultery”,
in the case of lesbians?