There is no promise of 72 wives or virgins for martyrs, terrorists or suicide bombers anywhere in the Quran.
This concept came from fake man made sick hadiths attributed to Prophet and collected by Persian Imams.
1- Abu Sa’eed Al-Khudri narrated that the Messenger of Allah (s.a.w) said:
“The least of the people of Paradise in position is the one with eighty thousand servants and seventy-two wives. He shall have a tent of pearl, peridot, and corundum set up for him,(the size of which is) like that which is between Al-Jabiyyah and Sana’a.”And with this chain, it is narrated from the Prophet (s.a.w) that he said: “Whoever of the people of (destined to enter) Paradise dies, young or old, they shall be brought back in Paradise thirty years old, they will not increase in that ever, and likewise the people of the Fire.” And with this chain, it is narrated from the Prophet (s.a.w) that he said: “There are upon them crowns, the least of its pearls would illuminate what is between the East and the West.”
Grade : Da’if (Darussalam)
English reference : Vol. 4, Book 12, Hadith 2562
Arabic reference : Book 38, Hadith 2760
2- Narrated Al-Miqdam bin Ma’diykarib:
That the Messenger of Allah (ﷺ) said: “There are six things with Allah for the martyr. He is forgiven with the first flow of blood (he suffers), he is shown his place in Paradise, he is protected from punishment in the grave, secured from the greatest terror, the crown of dignity is placed upon his head – and its gems are better than the world and what is in it – he is married to seventy two wives along Al-Huril-‘Ayn of Paradise, and he may intercede for seventy of his close relatives.”
[Abu ‘Eisa said:] This Hadith is Hasan Sahih.
Grade : Hasan (Darussalam)
Reference : Jami` at-Tirmidhi 1663
In-book reference : Book 22, Hadith 46
English translation : Vol. 3, Book 20, Hadith 1663