I can't speak to what @joeylittle thinks of this, but my guess is that he had already stepped into that role, and so it continued. I don't think he was putting on an act, not at all. He just continued to play the role he'd already reprised. But if things had continued for more than six weeks afterwards, do you think he would have stayed that way? Could that be part of the reason he changed his mind -- because he realized it was all fantasy and he wasn't really who you wanted him to be? (Not saying he's bad, but maybe just not quite the same as he was with you).However, how can you account for the fact that after therapy ended he was still kind and accepting and everything I had always wanted in a partner?
That's why I call it a fantasy. You knew that there was an obstacle. Instead of both of you choosing to navigate the situation healthfully, you decided to indulge and therefore render the actual realization of this relationship, impossible. Whether you knew that consciously or not - that was the choice you both made. And it's likely you each had different reasons.
I think this point is really key. Fantasy vs. reality. He chose to go the fantasy route, and once reality came knocking on his door, he walked away. That should be a pretty strong indicator that there was a deeply unhealthy dynamic here. I don't think anyone is saying that you two didn't care for each other, or that he put on an act and deceived you. I think the point is that the relationship formed out of an unhealthy dynamic. It almost seems like it was about fulfilling a need, for both of you. Love isn't about fulfilling a need; love goes way beyond that.
I think you're putting a lot of the blame on his business partner and thinking that perhaps she threatened him with legal action and that's why he chose to walk away, but even if that is the case, what does that say about how committed he was to building a life with you? I think Joey is right -- this was about fantasy. That doesn't mean it was all a big lie, or that he was deceiving you, it just wasn't build on sustainable foundations.