All of that backround on Triss really helps to flesh out as to why she was so composed when you meet back up with her in W3. She knew she was in the wrong, even jokes about taking advantage of Geralt.
True that. She definitely understands that the jig is up, because now Geralt remembers once more and the game makes it evident that their relationship should be over for all intents and purposes.
Yennefer also makes a few references when the game begins and those can confuse or frustrate newcomers. But these snide comments are not coming from " just some jealous person".
Imagine living decades in a marriage and then suddenly losing your memory as a result of trying to save your wife from some horrible situation. And then another person, who happens to be a close family friend and essentially a sister figure to your daughter, takes advantage of the situation.
It is hard to dislike Triss but she is captive to her emotions and desires. One can't but feel sorry for her.
To lose her status in the royal court is a tough pill to swallow. When she meets Geralt in Novigrad the situation is extremely tough as Triss is trying to stay alive at that point.