>>50788968The lack of proper dexterous limbs and any manner of grasping appendage / psychic manipulation besides her mouth is a possibly insurmountable limitation for genuine romance.
It would be a one-sided, taxing, unequal relationship much like one with a physically disabled person.
Maybe little different from an ordinary trainer-pokemon bond where the trainer provides everything for the pokemon in return for affection.
Housework, cooking, and the like most likely aren't possible with inflexible, fused flipper bones.
Unless those flipper lines actually separate into fingers, what can she do for you, physically, as a partner? Besides the obvious mind-blowing mermaid sex.
It means a lot of self-sacrifice that wouldn't be necessary with a Gardevoir or similar that could reciprocate effort made.
You'd have to really, really love her and be willing to give up a lot for it to work. Particularly difficult choice for a waifumon.