Feel a bit sad and unwanted

Quite the opposite Skydancer you should be congratulating yourself on a job well done. You have helped to bring up your grandson to be an independent young man and been a big support to your family. Now it's time to follow your own interests and hobbies.
Why don't you suggest the occasional mert up with your grandson because you will miss him not because he needs looking after. Enjoy this new phase of your life.

Don't feel sad. They weren't wasted years as you have made lots of happy memories for both you and your GS

All you can do is take a step back but he'll know that he can call on you if he needs help

I was commuting to work in London at 15 so I don't think you need to worry too much about him!

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You haven’t wasted years skydancer, you have had 15 years f joy with your gs. My gd is 12 and no longer funds playing shops and schools anymore, and yes it does make me sad too so I do understand but we both know this is what happens and we have to look forward to the next stages in their lives.
A 15 year old boy woukd be strange if he felt he needed to be looked after by his gran, but it doesn’t mean he doesn’t love you. Take care [ flowers]