Good girls don't typically trip the light fantastic, fantasising about men and women other than their spouse when the spouse leaves for a few days. She used to lament, and now she still laments, but she also does what she PROMISES herself she will never do again: troll around, looking for some hint that she is similarly adored, as she similarly adores. Her partner (the real one) is beautiful and as dark as she. They both have demons, and those demons aren't only on a first name basis with one another, but pleasure each other in the seediest and darkest ways they know how.
It's just that she was 19 when they met, and had only skimmed the surface. He was the first one to really admire her for who she was. Who loved her giddy tangents highs and used to coax her out of her deep, throaty lows.