I cheated and don't know how to fix it

okay so Im in my teens , i was on holiday and I kissed someone else, it was only a kiss to me I don't think it means much but to my partner he's lost all trust on me. He ended the relationship but nothing has changed at all, including how we are sexually.am I being used or is it normal that he won't get back together with me after this sort of 'betrayal' if you like