Should I bring this up or move on?

I was cleaning my boyfriends apartment while he wasn’t home and in his closet, I found a letter from a girl that was written to him during our 2 month break a year ago.

He had told me that he tried to date other people, as did I, but that it didn’t work out. I accepted this and moved on. But when I found her letter... she was talking so romantically about how their last night was so amazing laying under the stars blah blah blah.

Anyways, in a furious rage, I burned the letter. I told myself I wouldn’t let this ruin my night and it was cool. Until I kept cleaning and found his response letter. A long well written poem in which he told her he loved her. He never sent it. We started officially dating again a month later.

It made me feel really grimy and it really hurt my feelings. So I burned it too. I know I shouldn’t have burned them, let alone read them. I was just trying to organize papers and throw away things he didn’t need, as he has so much clutter and receipts and stuff from years ago.

I thought about bringing it up to him, but instead, I cooked him a delicious dinner, and acted like my usual sweet, fun loving self, reminding myself that this happened before we started actually dating and that he never actually sent the letter.

I think what hurt the most is that he’s written me so many unique poems, but reading that letter was a punch in my heart. Should I forget that I read it? He doesn’t know what I did during our time apart either and I wouldn’t want him to know, so I feel like I overstepped a boundary and getting mad or upset would be hypocritical.
Should I bring this up or move on?
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