Get a second TW.
1) Your boys will feel less like second class citizens if they ride the same bike as their Dad is riding. Young adults appreciate being treated as young adults. They can more readily learn by mirroring your style and techniques better than if you were demonstrating atop a KTM 530EXC.
2) When something goes wrong with one TW you have a second TW for comparison purposes as well as parts exchange for a diagnostic aid. This really comes in handy when trying to decide whether to buy a new carb, a new CDI, or stator source and pulse coils
3) Get a third more powerful bike when the wife isn't looking.