Sayyed Muhammad Husaini Ragheb, Sayyed Muhammad Husaini Ragheb has a BA in Law from Guilan University, Iran and has also undertaken Hawzah studies in Qom. He is a Cultural Affairs director of Ethics Group of Al-Mustafa Open... Answered 3 years ago

The significance of marriage is to the extent that it is said that one will save half of his/her religion by getting married. It means that the potentiality of getting involved with sexual sins decreases by getting married.
As for the second part of your question, according to the popular viewpoint of Maraje' a Muslim man can marry an ahlul kitab i.e. Christian, Jew or Zoroastrian woman in temporary marriage only and not vice versa.