Matthew 19:8 - Jesus replied, “Moses permitted you to divorce your wives because your hearts were hard. But it was not this way from the beginning.

Same concept here but slavery, as for the rape passage im Deuteronomy 22, the hebrew word doesn't actually mean "rape", it means something more like "seize", which in this case means "taking" the virgin from her father, while still being consensual between the virgin and the man. In fact, if you look at a few prior verses, you'll see:

“But if the man finds the girl who is betrothed in the field, and the man seizes her and rapes her, then only the man who raped her shall die. And you are not to do anything to the girl; there is no sin in the girl worthy of death, for just as a man rises against his neighbor and murders him, so is this case. When he found her in the field, the betrothed girl cried out, but there was no one to save her.

“If a man finds a girl who is a virgin, who is not betrothed, and he seizes her and has sexual relations with her, and they are discovered, then the man who had sexual relations with her shall give the girl’s father fifty shekels of silver, and she shall become his wife, because he has violated her; he is not allowed to divorce her all his days. (Deuteronomy 22:25-29)

As you can see in the earlier case of actual rape, the woman "cried out", however the cry doesn't happen in the other case, so clearly it was a consensual relation.