I think 'planning' sounds rational and deliberate to people like us.
It probably wasn't particularly carefully thought out on his part- more that rather than understanding automatically that as a child you needed protection, he saw you as just another object he could manipulate to his own ends.
He got a kick out of being powerful, being able to toy with you, to become important to you. Not for your benefit but for his. And then in the longer term he was able to use you for whatever gratified him.
He undermined your development of boundaries.
Have you heard of the shark cage? We help our DC build a protective cage around themselves, that keeps predators away.
When our parents are shoddy, and when men like him get involved, we end up with very gappy bars on our shark cage.
It starts when your parents ask you to lie (say you're four, not five. Don't tell your dad). It carries on when you can't tell them the truth about things because of the trouble you'll be in. When they blame you for what other people did.
This man spots that you have an inadequate shark cage and joins in the process of keeping you vulnerable. (It's just one, no one cares. It's ok, it's just me. But I helped you, I thought you cared...).
Al that pressure and manipulation, you don't know where your bars should be. You don't recognise red flags.
Not your fault.