Very similar situation here as we played together for 20 plus years, went our separate ways because life takes us in different directions sometime. After both retiring we got back together briefly before Charlie's passing.

Because of my age (old guy) I just moved on to playing solo gigs. With this said if I were younger as in your situation I would first take some time to reflect on all the good times, then when you feel it is time to move on I would start auditioning bass players.

But I promise you this, there will many many instances when you will either hear one of his licks, or even better feel him with you on stage.

Hang in there,