Well done! I loved when we paid off our mortgage (about 4 years ago) because it dramatically reduced our ongoing monthly expenses.
The first thing I'd do is set a side a small amount to celebrate the occasion in a manner that you wish. 10 years is a very long journey so during this time you want to make sure that you recognize and celebrate your path. The path should feel natural and make you happy.
The second thing is to ask yourself, do you like (and have time for) actively managing money or experimenting with money? If the answer is no, then the path is relatively easy. Open up a vanguard/fidelity account and buy index/funds with low fees with an AA that reflects your plans.
If the answer is yes, then there are so many options like dividend growth investing, real estate, P2P, crowdfunding, art.
I'm the latter, I've chosen to do index's for my retirement accounts. For my after-tax accounts, I invest in dividend growth and real estate to generate passive income, which pays for a significant part of our monthly living. I'm also exploring crowd funding in real estate.
With this passive income coming to me, if something happens at megacorp I wouldn't bat an eye.