Okay so this is gross as fuck and I'm totally at a loss. I started dating this guy last spring when we were seniors in high school. This year we're at different colleges a couple hours apart so we're in a long distance relationship except for school breaks. About once a month we send letters or little gifts to each other. He's really great and cares about me and has never shown any sign of being, well, unstable or self-harming or whatever over the time we've been together.
So today I got his monthly letter and gift in the mail. The gift was a little wrapped box like what a ring would be in (for a second I thought he was proposing and was a little freaked out as we've never discussed that) but it turned out to be way worse. In the box was this kind of shriveled bloody piece of skin/flesh about the size of a quarter. I was totally freaked out and wondering what the hell he was doing and thinking it had to be fake or a joke of some kind. I read the letter and in it he explained that he's sure by now that he loves me and as a sign of his love he cut a piece of his flesh out from above his heart and sent it to me to "symbolize his love and devotion to me." I felt sick and chucked the box in the trash.
He's been texting me and is asking what's going on because I haven't been responding. I'm still trying to process this. Who cuts out a chunk of flesh and mails it to someone??? Literally apart from this there haven't been any issues except the usual occasional arguments that we eventually resolve. Is this a sign there's something really wrong with him that I just haven't seen and if so should I break up? At the very least I don't want him to ever do something like this again. How should I let him know how much this disturbed me without making him feel bad or do something worse?
tl;dr boyfriend of almost a year sent me a piece of his flesh in the mail as a "sign of his love." I'm very creeped out and not sure what to say to him.