Spoilerssss

I have my speculations, the younger twin obviously doesn't actually like MC's cheating ex, he's using him, idk if it's to feel a sense of superiority over his twin? Sadism? Whatever it is, younger twin is clearly the golden child and relishes in that fact.
I'm assuming he's made a deal with ML's older brother (the beta) just like how our MC made a deal with him (although that deal was forced because of his parents), and he either is doing it to get paid, or because he saw a picture of the ML and thought he was hot.
Either way, what's gonna happen is: MC who is already feeling guilty for wanting to stay is gonna think he has to leave because the original deal says he's just a temporary replacement, he'll think that ML will wanna be with his twin because A: MC thinks ML doesn't realize he's a recessive yet, and once he figures out that MC has been lying to him he's gonna want to be with his dominant twin (especially since that's what the grandpa household head wishes for) and B: MC has been living his entire life being told his twin is better than him, so he's gonna think ML will leave him for his twin just like his cheating ex did.
ML: will not let MC go, or will fake letting MC go and fake going along with his brother's plans, but will eventually ruin them and go after MC
MC's twin: will fall in love with ML and will guilt MC for wanting to stay (maybe even with the help of his parents), he's gonna believe ML actually likes him and will be shocked when it's revealed that he's not. He's also gonna have some drama with his "boyfriend" (cheating ex)
ML's brother: since he made a deal with the grandpa that if his younger brother ends up with a dominant he'll benefit greatly (maybe get a huge chunk of assets or become the new household head) and since there are hints that he might start to like MC, he's gonna be a big obstacle to the MC and ML staying together, he might try to get with the MC too.
All of this is speculations I made from my years of reading BLs, I hope to be wrong and be surprised for what the author has planned, but if this is also the result then I don't mind either. But that also means that all the challenges and obstacles are gonna be built on miscommunication and lies, which to be fair, is already the case lol

Way full of dreams..i obviously kinda assumed that ml looks too obsessed with mc..don know bcz of his pheromones or whatever,but mc twins coming back..i think will leave to drastic changes in upcoming chapter... anyways..we will find when it'll come back..
Thk u so much for clarifying alot of things to me...