Well

If you re read again from the beginning, i think the seme really wanted no string attached, bc he has abandonment issue (trauma for being left by mom) but couldn't help getting attached and in love with the uke. and the uke was "obedient" to him, playing lowkey, Noah made it obvious that he also didn't wanna get attached as he never stay the night after they both fuck (for different reasons) , noah always came home and never sleep together after sex.

And the time when seme's injection suppressant fell near the uke, I have a theory seme did that on purpose to test Noah if he would still come. Idk, I feel like the seme didn't expect uke to turned into omega, bc if noah stayed as a beta, he could easily inject the suppressant to the seme.