I dunno about Bangladesh, I don't even know too much about places like UK or NYC...but the Bengali girls in my community...80% majority are marrying "shada" who they meet and date while in undergrad, grad school, etc. Of course there is a public conversion to Islam and whether or not they really are Muslims is actually none of our business nor our concern.
I would NOT hesitate to predict that more than half of the Bengali Muslims in the US will end up marrying "shada". To each his/her own. Interestingly I'm not sure how many Bengali-other desi marriages there are. I know of 2 friends who both married Pakistanis, I'm scheduled to attend another Bengali-Pakistani wedding in 2 weeks, and my cousin married a Malayali south Indian, but apart from that I don't know too many.
Cricket cannot live with the mistaken belief that people want to see big hits. People like to see goals, but no one is talking of moving the goalposts a metre wider either side. (Harsha Bhogle)