I've found that hurting people's feelings is inevitable. If you stay with her, she is going to get hurt or offended and you two will have emotional pain. If you stop being her boyfriend, then she'll likely get hurt and sad; it will be a short term pain. I remember a guy sharing a story about his wife. From what I recall, the two of them went on a date and the girl didn't want to go on any more dates. Two years later they started dating and not long after that got married. The man said that looking back he was glad they split up after that first time dating because they weren't....right?...for each other. Basically they weren't emotionally ready a serious relationship.
Consider these words, "For all sad words of tongue and pen, The saddest are these, 'It might have been'." What will you regret if you married her and nothing in your relationship was different?
~John Greenleaf Whittier
Quote obtained from https://www.brainyquote.com/quotes/john_greenleaf_whittier_385048