Some misunderstand Christian views on sex and assume sex is a dirty thing that God finds disgusting. Paul says sex within marriage is a good thing. He also gives flexibility on the issue of marriage. If a person is single, that is a great thing if the person does so in order to serve God better, but marriage is the right choice for many who cannot avoid sexual temptation. That doesn’t sound very romantic, but Paul seems more concerned with doing the right thing than romance. He also emphasizes the permanence of marriage, just as Jesus did, with limited exceptions.
People’s views of sex and marriage can be different than God’s, but God’s view is designed for our benefit. When people adopt more casual views, sex and marriage become meaningless. Is life really better without commitments to God and each other?