Dude just needed to gain a few brain cells and research Yanderes / how to emotionally manipulate someone. He could've turned the tables on her before she died but he was too dumb, weak or innocent to Uno reverse the situation.
After she died he got conned. Honestly I don't feel bad for him. He lost to her twice.
That said, he should be able to move on but she couldn't cuz he was her reason to stay. He has none now, she told him everything so there's no guilt, she drove him to do everything with manipulation. He should ascend to heaven or whatnot while she's stuck because she didn't factor in the fact he never really loved her n the first place because she drove him from it.