That's an interesting way to put it, but I totally agree - it's the wrong next step for them to ignore their fight, but at the same time they had to have that fight to open up to one another and get close enough to take the next step physically, too. (I also like using sex, and sexual progression, as a metaphor for emotional closeness.)

I would argue, however, that Charles has been fighting Erik when he thought it mattered all along - it's just that Erik always bails on their arguments before Charles can win! He wasn't too squeamish to kick Erik in the injured leg in the middle of an argument, for example, in Part Three. He's just the quiet sort of fighter :)