[Robodog]

Firstly, it's true she mentioned the argument involving Jim and her husband etc before she even entered the house on launch night.
Jim obviously heard her say all that as he mentioned it in his last noms for her. So she was clearly the one to bring up their past argument first.
Fair enough then that Jim referred back to it a week or so into the show when he said about carson's dressing room. He didn't mention it straight away, nor do i believe he actually wanted to refer to their previous history at all whilst in the house.

So why didn't he mention it straight away after he had heard Linda refer to it on launch night? Because he wanted to avoid it and try and keep peace.

Why then did he mention it a week or so in when he said about frank c's dressing room? Because all his other attempts at peace with Linda had failed!

She had been on his back from day one. Rallying others against him. Trying to constantly provoke him into an argument and even when he walked away from her conflict - she still continued at him.
This went on and on and on until finally he cracked and said something back in retaliation by hinting at the frank incident which he believed to be at the root of her endless problem with him.
I think he regretted saying about it but i feel he was ground down by her and exhausted and frustrated by trying to be civil with her and it getting nowhere.
Metaphorically, she had been throwing stones at his head from day one which he ignored. But he is human and can only take so much - until finally he turned round and threw back a single brick.

Remember - it wasn't Jim's first choice to say something. His first choice was peace and to walk away which he did for days on end with her. He only said something because she left him no option.

And to be honest - i think it worked. It didn't stop her but it definitely slowed her down for a while and gave him some breathing space. Maybe it did her good by making her reflect on the wider picture rather than just attack Jim automatically as she had seemingly come to do.