Here we see the Cleopatra character a bit older now, and very pregnant. Although she lives a stable life with her husband, she knows she is still unhappy. Her character, is someone who wants to keep moving and life has slowed her down from that. This is what causes her "what if" split to happen. Had she left when she wanted, she believes she could have been so much happier.
"When you left this town, with your windows down
And the wilderness inside" ...
"But you held your course to some distant war"
In the corners of your mind
Her story does not go into detail about where her desire to run comes from. If it was her core, why hadn't she left with her love when she did? Was her time to leave her current husband her way to feel back in control of a choice she didn't make so long ago?