Things that make me sad.

I just found my ex-boyfriend's t-shirt in with my stuff from last winter. I don't know what to do with it. If I keep it I think it'll hurt my boyfriend's feelings, and I don't want to do that, he's perfect, he makes me happy...
But if I chuck it away then I'm breaking his promise... and it's the only thing I have left of him from when it was good, if I get rid of it I'll only have the bad memories...the knives, the tears, the guilt, the acid... Shit, I haven't told you about the acid... not much to say really... other than I found out he want(s/ed)to throw acid in my face... I probably deserve it to be honest.
But I don't know what to do.
What should I do?