Friends with benefits, becoming confusing?

Hey ladies, so this will be a long post.

There is a man I have been "seeing" on and off for nearly 4 years. We have always been close, since day one. We have moved on at times and started seeing other people, but as soon as it comes to an end we are jumping back into each others bed and arms. We have a strange relationship. I feel deeply for him, and he says he feels the same. It is an "I want you to be happy, regardless of everything else" kinda thing. We do say I love you before we go our separate ways, always have.

Well last time we met he told me that he had told a woman he had been having sex with something that he tells me in the bedroom. This woman doesn't enjoy the things he told her to do, so it was clearly a case of talking to her but thinking of me. He has admitted to having me in his mind during sexual acts. That when she was over at his house he "kept looking at her but seeing me".

Maybe I am overthinking, but it seems like his feelings may be becoming more intense than a simple friends with benefits relationship like before.

Am I just thinking too much?

Or could his feelings be getting deeper?

Our relationship is very complicated haha