I guess it started happening after she accused him of being dhokebaaz , biased & jhootha.
Thou he don't say much but do collect what pakhi do to show sai down.
He was bit pissed off when he learned pakhi did tamasha infront of family for him bring food 4 sai.
He himself had started getting irritated by pakhi.
He got an idea that sai get pissed of by his communication with pakhi & what she thinks about it.
So he started avoiding him as much he can thou pakhi didi not ready to leave him coz she is human fevicol.