Is it permissible for a husband to insert his penis into his wife's anus while using a condom, knowing that some consider this forbidden because it is an impure place?

The ruling on anal sex with a woman has been previously explained in fatwas: 30715, 35037, and 33871. This ruling encompasses anal sex with or without a condom, as impurity is not the sole reason for its prohibition. There are many other reasons known only to Allah.