Evil Morty and Rick are the sort of situationship where sometimes the tension of battle leave them needing to blow off steam but neither of them fully want to admit that they’re thinking of someone else when they fuck
but that also didn’t make their personal chemistry not mean something either.
I like to headcannon that Evil Morty does actually love his grandpa, and I do think he misses his rick. But i think that relationship ended bitter, which is why hes so convinced that Ricks don’t care about mortys. Maybe he got rejected, maybe his Rick was particularly abusive. Who knows.
Rick on the other hand just straight up loves his morty. He never had a chance to have his own family, his own morty. So, Morty is cosmically a representation of that connection to his family, to his humanity. He is someone he can genuinely trust.
I dont think c137cest is fully cannon (yet) even if I think Rick and Morty acknowledge their strange relationship and love for eachother. I don’t think either of them (at this moment in time) have fully crossed that threshold yet, even if they accept its a possibility for their emotions/relationship.
However, I think Rick and Evil Morty definitely have. Mainly because they’re both selfishly using each other for their benefit. Rick gets that morty attaction out of his system allowing him to feel more normal when at home, Evil Morty gets his grandpa issues out of his system so he can focus on living his life. Its a Win Win.
Ultimately tho Evil Morty is defo jealous of morty prime tho esp since he knows everytime rick moans his name it isnt actually him rick is thinking of