Q.  I heard that some don’t get married on nitel night, is that true?

A. Horav Shlomo Miller’s Shlit’a opinion is that for those that observe the minhag of Nitel, it depends on the rationale behind it. If the reason is the inherent avelus and mourning on a day that caused historically so much pain and tragedy to our people, (Korban Nesanel, Chasam Sofer 2) weddings should be avoided. Nitey Gavriel (Nisuin 1: 48: 18 – Chanuka 5: 4) indeed quotes opinions that some avoid getting married on Nitel night; that being also one reason why we don’t learn Torah on that night, as Torah learning creates simcha and joy.
However, if the motive for Nitel is the habitual sakana or danger for Jews being in the streets on that night, (Taamey Haminhogim) it may not apply in our days.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a