We have a small apartment within our house (it has its own kitchen and bathroom, but not its own entrance). We often have people staying there, single people or families who are trying to get on their feet. We don’t charge them rent, though they pay for utilities if they can. So our situation is somewhere between that of landlords and that of hosts. In such a situation, is it our moral responsibility not to accept unmarried couples? Does it matter if the situation is something of an emergency—f…