@Yogi - In Bhagvatam skanda 10 , chapter 53 ,shloka 48 , we can see the mentioning of Mangalsutra - This chapter is about Rukhmini Haran , where Rukmini worshipping Ambika devi and Brahmin and their wives , Although the word used for Mangal Sutra is "Kantha-Sutra" कंठ सूत्र but Gita press translation of Kantha-Sutra is mangal sutra.-
vedabase.com/en/sb/10/53/47-48