I have never been married, so I cannot say what is or isn't possible for married people. I only know that I have felt like I was in love with multiple females at once, and I'd have no problem with marrying any or all of them.
What is impossible for a woman is not necessarily impossible for a man, or vice versa. I cannot bear children, for example. Perhaps a serious and spiritual relationship with multiple spouses is easier for a man than a woman.