My 18 yr old daughter is not talking to her 16 yr old sister because the younger one is dating a boy that the older one likes. The boy isn't interested in my 18 yr old but he seems to like the 16yr old plenty and they are dating regularly. This has been going on for 3 months now and I am getting very upset. I don't think it's fair for the older one to "punish" the younger one for this but nothing I say makes any difference. I hate having this tension in the house.