[It's not easy on any of them, and Gai knows that he has a duty to Konoha that he needs to fulfill, but to lose Kakashi is such a high price. Part of him wants to suggest that Kakashi stay here while Gai and Lee go back, and then Gai comes back to visit, but even that's just a stopgap measure.]
If Gai thought that Bell would be all right with that he'd do it in a heartbeat.