Im glad it apparently didnt damaged their relationship, but i hate how this was taken so lightly.
If it were me in Kawasumi shoes... that person wouldnt ever have my respect again. Thats called betrayal. He went behind his back, took advantage of her innocence and lack of awareness all the time, dragged her publicly knowing they already have problems with the people at school and even confessed to her and asked her to hide it. That was despicable, more over to actually have the courage to say Kawasumi wasnt acting like a man for being jealous.
But the thing that bothers me the most is that Suiren is not cut to be left alone at all. That guy could had kissed her if he wanted too. She just froze when he got close to her face. Not even tried to avoid it in any way. She didnt even took that seriously.
It scares me to think that if a random guy dragged her she would also froze.