Based on the context provided in the poem "Molly Maguire at Monmouth," without specific details about each character in the painting, it’s difficult to definitively determine who Molly’s husband might be. However, typically in art and literature, a man who appears to be actively engaged or showing admiration, such as the man raising his hat behind Molly, might be seen as her husband or partner. Therefore, my interpretation leans towards:
the man raising his hat behind Molly as the most likely candidate for Molly’s husband.