I'm an absolute fan of this couple, so hm just my perspective I guess. They're like a married couple at this point, Morinaga understands how Souichi shows his love and he also understands that he accepts Morinaga's affection, Souichi made it clear from the start that he isn't used to affection and that his limits are different from Morinaga's and Morinaga accepts that, love is about compromise and although they do take small steps, (because this is a long ass comic and doesn't seem close to ending either) with every volume they understand each other more. Also, Souichi was never focused on a Romantic relationship, especially with a man, so that's also a huge compromise on his part- they're happy with each other, and they're actively putting effort into their relationship with every new volume. I don't think they need jealousy or to feel the pain of loss, they've already gone through that, they both deeply care about each other but just express their love in different ways.
But with all that being said- I get what you mean and respect your opinion ٩(๑❛ᴗ❛๑)۶
I king of want Morinaga to move on from senpai and find someone who can actually return his love. Even if senpai has developed a lil more compared to the beginning Morinaga deserves someone who is proud of their relationship and can return his affectionate love... even if it’s only temporary and maybe senpai will see Morinaga’s worth in his absence.