<human>: Just some backstory; Me (17m and her 18f) were in highschool and had been dating for a year and a half.  We both were REALLY close at this point and had talked about dating in college and stuff and we got along perfectly.  One day though, she told me she had been going to see a 'friend' of hers at like 3 am on weekends and hanging out with him. Nothing sexual, just hanging.  

She then went on to tell me she still loved me but had been cutting herself because of how guilty she felt.  I felt an insurmountable guilt because I felt like I shouldn't have been at all mad (I never yelled just got a little ticked off), since they never did anything.  

Anyways, she struggled with this for a couple weeks, and eventually came to me to talk.  She had problems talking with me about things, but managed to talk about her issues, and at the end made me promise to take the switchblade she was cutting with.  I reluctantly agreed.

Time passed, awful breakup, we became really really close friends after a while, were on and off for the rest of the year.  Then I went off to college. We got in a big fight and I forgot about her

My point is that the other day I found the switchblade, and it really hit home.  I'm actually studying psychology because I was so interested in mental disorders because of things people have told me in the past.  I know I should probably toss it and just move on because just knowing I have it keeps her on my mind every now and then.  At the same time it always keeps me encouraged to study hard and is a reminder of why I want to learn psych.

Could you distill the essence of the text into 1-3 sentences?
<bot>: Should I keep or throw away a switchblade my ex used to cut, even though there's some pros and cons to keeping it.