>>715741334
No, they were just doing the same thing they did in VII where you can go on a date with someone other than Aerith at the Gold Saucer. The dream sequence where it appears that Jecht is 'stealing' Yuna and Rikku from Tidus is just Tidus' mind projecting his resentment because as a child he thought Jecht manipulated his mother's affection, when we find out later that it was in fact his mother who completely ignored Tidus in order to cling onto Jecht when he was around.