If this sounds like a solidly weird sci-fi/fantasy novel to you, you'd be correct, but boy does it wear it well.

Matt and Charlotte, are young, vivacious, and just married. They haven't started to hate each other yet. Waking up the morning after their very normal wedding, they each wake up to find a not-quite-right version of the other. Oh, and Charlotte's somehow managed to get on a space ship, with a humanoid creature that seems a lot like her very normal cat to boot. Everything is decidedly strange and the not-quite-right versions of their partner are even stranger, babbling of stories and sentient frogs.

Full review here: practicallyuntitled.blogspot.com/2020/05/sentientfrogs.html