"Erase an entire part of your life because I am too insecure and jealous that I cannot even handle thinking about you remembering another girl other than me."

That seems incredibly understandable, yes. My girlfriend and I still discuss our old relationships to the point of reminiscing about them. Hell, she still talks with the first guy she was head-over-heels in love with. It's pretty outrageous for her to even suggest erasing an entire part of your life. And for you to go along with it in hopes that it makes everything better? They call that being whipped and dependent. And now she knows she can get whatever she wants out of you by being overdramatic.