Ask them how long their own relationships last lol. Even high school relationships are likely to fail, elementary, yeah right. Honestly, in elementary, it's not what I consider a true relationship, so don't even worry about it. Plus, I'm in 8th grade, 13, never been in a relationship or had a crush, so I just don't worry about stuff like that. Just ignore people like that, if they persist, then tell them to shut up, if they don't, just don't associate.