He needs something that's going to take him away from the island. In a way, he both desperately needs his friends from TR, but also seeing them reminds him of how much he's still missing. Having Grace or Steve would help, but so would anyone from Hawaii at this point.

He'll be able to move on, but it will likely be akin to how it happened with Rachel in that it took years for him to find someone to be serious about (and he relapsed with her, so yeah, he has issues)