In a typical Christian manner, you didn't read the entire passage, in which Jesus heaps contempt on marriage. That verse is Jesus explaining why you can't ever get divorced if you marry, which he follows up by explaining that getting married is bad in the first instance -- we should instead live like eunuchs for the Kingdom of Heaven. Full cite:
19 1 When Jesus had finished saying these things, he left Galilee and went into the region of Judea to the other side of the Jordan. 2 Large crowds followed him, and he healed them there.
3 Some Pharisees came to him to test him. They asked, “Is it lawful for a man to divorce his wife for any and every reason?”
4 “Haven’t you read,” he replied, “that at the beginning the Creator ‘made them male and female,’[a] 5 and said, ‘For this reason a man will leave his father and mother and be united to his wife, and the two will become one flesh’? 6 So they are no longer two, but one flesh. Therefore what God has joined together, let no one separate.”
7 “Why then,” they asked, “did Moses command that a man give his wife a certificate of divorce and send her away?”
8 Jesus replied, “Moses permitted you to divorce your wives because your hearts were hard. But it was not this way from the beginning. 9 I tell you that anyone who divorces his wife, except for sexual immorality, and marries another woman commits adultery.”
10 The disciples said to him, “If this is the situation between a husband and wife, it is better not to marry.”
11 Jesus replied, “Not everyone can accept this word, but only those to whom it has been given. 12 For there are eunuchs who were born that way, and there are eunuchs who have been made eunuchs by others—and there are those who choose to live like eunuchs for the sake of the kingdom of heaven. The one who can accept this should accept it.”
You literally could not have chosen a better example to make my point about modern Christian incomprehension/unawareness of what the NT actually says regarding marriage, so danke. Modern Christian views about marriage are similar to modern Christian views about the poor -- it now turns out that Jesus advocated getting rich, paying no taxes, getting married, buying an SUV, and watching a lot of television.