Lyric discussion by clovus 

Cover art for Across The Great Divide lyrics by Band, The

I think the "great divide" here is between married life and bachelorhood. You lose control of your life ("take a ride"), get married, and baptise your children ("at the riverside") when you have them. The other verses are about his youth, and it seems he may have cheated on Molly with the queen.

Molly, clearly, is ready to cross the great divide, and is not too happy that he is not coming with her now. That unhappiness gives us that great line, "Now tell me hun, what you done with the gun." He tries to console her by indicating that she'll find someone else that she can "feed...chicken" to every Sunday.