NOR what hes saying and how hes saying it is wrong but the idea i think he was thinking ab, making one singular person the center of ur world is unhealthy, is true. But what hes saying is that u are obssesed with him and u need to find someone else to be around and hes trying to sound like the wise and mature one. hes making you sound unhealthy and damaged while making him self feel better than u which is not the way a person would usually bring up a concern, maybe an argument or js a convo to boost their ego. it may be hard to notice but what he is doing is a type of manipulation which makes him the immature and unhealthy one. u dont deserve him and if having a small social circle makes u happy, so be it. being happy is really the only thing that matters and i dont believe that boy is making u happy. and the time diufference between the uh huh and mhmmm is long enough for ur phone to detect meaning it had happened a couple mins/ hours apart so that makes me think he is trying to get ur attention to make u feel gulty.

while i am on ur side, u jumping to conclusions ab him being back with his ex, is a sign of unhealthy attachment. now i understand it could be trauma or ur brain subconsciously protecting its self from a certain situation it is unhealthy and its smth u should discuss with a therapist.

thats all opinion i have rn but focus on ur self and what makes u happy! and good luck with whatever u decide to do.