i like how their relationship develops both in books and games combined. From curiosity to the unfulfilled love, relationship, to Witcher 2 when i felt that Triss knew that it will end someday. in Witcher 3 their romance arc was a little cheesy, sure, but i would be lying if said I didn't enjoy it very much.
I don't know if I would say cheesy but, it can come off that way I guess because Triss is more giggly in a sense. I mean imagine if you loved someone so much for years but couldn't have them because they were with someone else. How would you react if you are thinking, this is goodbye, thank you for the memories I know you are going back to your love, then all of sudden, they turn to you and tell you they love you and pick you over the other person.