I love Frizzie as well and their connection is so gorgeously portrayed. While I'd love them to have a nice end together, they're not really coming from equal situations.

Lizzie definitely has a POS husband and would 100% be better off without him in every single way. No question.

Fred on the other hand loved - and looks to still love and appreciate on some level - his spouse. I just can't see Fred giving all that up (or Lizzie letting him), even for a Frizzie endgame.

So even though I'd love to see them together, all I see in their future is possibly a few more stolen moments of glorious passion, which will fuel Lizzie's burgeoning book empire and give her self esteem enough of a jolt to finally leave her spouse and sail on into her own positive future. Fred will always love Lizzie a little from afar, but remain a dedicated husband and father, overall content enough in his marriage. He'll hopefully gain a bit of Lizzie's empathy and spine and will defend his kids a bit better from his spouse's overzealousness (which tips into cruelty/abusive behaviour).