He used Sid to come so further in the game. Sid guided him and always stood by him throughout like a true friend and elderly brother almost. People are saying Asim saw Sid's true colours now he woke up etc but NO that's not the case its vice versa Sid saw Asim's true colours and he is hurt and shocked.
He knew Sid is the most popular in the house and outside too most well known name and he clinged on to Sid to come to far in the game because NOBODY really knew who the heck Asim was before BB.
Now he chucked him away like trash.
There was better ways to explain to Sid if he felt bullied or bossed around or whatever he is saying he is also aggressive and we have seen it when he used to fight with Paras in the starting of the show!
Asim was nearly invisible during the starting episodes and it's when him Sid and Sana became a trio the game changed for him and he realised this is it now I will be seen. Now all this encouragement from Salman etc, his become overconfident and literally chucked away his "friendship" with Sid. And people are saying his a honest, humble guy?!
Trust me not only lost a true friend who genuinely cared for him, his ruined his game too - because heck is he gonna get any solid honest support from the dogla gang.
He started feeling jealous of Sid and ended up reacting the wrong way by provoking him and he isn't a dhood ka dhula like people are acting!