It is not the question of boy or girl.
Muslims are not allowed to give up Islam hence the other party needs to embrace Islam.
Do you know that Uttamchan Mohanchand alias Mohan Babu, who belonged to an affluent family of Rawalpindi had embraced Islam to marry a bollywood celebrity called Jaddan Bai. Jaddan Bai is none other than the mother of Bollywood celebrity Nargis. Again Bollywood actor Sunil Dutt embraced Islam to marry Nargis.
So yes. There are many examples where men have embraced Islam to marry a Muslim girl.
With regards to marrying multiple wives, Islam allows multiple wives as long as the man can afford to take care of them. There is no issue here.