As Moorthy was driving with Kathir back to their home , he was reinforcing the fact that Mullai was Kathir" s wife hereafter & he was to remember his responsibility on that fact. 
Kathir though accepted to marry her to save the respect ; they both were man & woman from then on.  He has to abide by it . The truth hit him hard now .
Kathir was able to perceive the reality of it more now . The thought of sharing life with a woman hereafter , got him really tensed .
He knew her.  She had wished his brother.  She didn't like him.  She s sort of overtalkative & lil bit fightercock when it comes to him ...

How on earth life is going to go on ...with this .

He found himself very pathetic .

Though looking tough on the outside _ Kathir really did possess a soft nature_ he had a vulnerability.  .
It was that ,nature that made him to stop studies & help his brother .
It was the same nature that made him so protective of Dhanam ,when she was targeted for her infertility issue .
It was that same nature ,that made him accept this marriage & tie the knot on Mullai "s neck .
But , till then.....it was only him who had to bear the consequences .
Hereafter it is not going to be so ......
That was the essence of Moorthy " s long speech. 
Moorthy had sort of tamed Kathir , atleast he made him to realise , there is going to be a girl all along with him in his life .
Kumeresan uncle"s ideology about ; fate deciding on one " s life partner also had made some impact in him .

Kathir was bit clear now .
Well , he was hitched with a girl .
His wife .
She ofcourse doesn't like him .
So does he. 
But , there was no way , running back .
He , or rather they would have to face it. 
He decided not to be mad with her for whatever she s gonna vomit verbally . ( It's her born character ) Factu Factu
Second , he wud clearly open up to her ,that she needn't worry over the physical intimacy issues .  Needn't worry ? 😏
Third , he wud make it very clear to her ,that he won't be calm if she s gonna pick on his family members . Apo ava yentha family memberu ?

Having decided so , he felt himself more calm .
He made up all these facts in mind and entered the ....their room .