By the time season 12 rolls around, Dawn is now twenty two and Xander is twenty nine. They're both adults. Part of me is happy for both of them- Dawn gets to have a decent, fulfilling life and Xander finally gets to settle down with a woman who loves him, who isn't a complicated supernatural entity of some sort -and he's the only one of the core trio of characters who actually gets to do so, moreover. So, good for them both. Bonus point for naming their daughter Joyce.