Oh, HELL I wish I had something useful to say. All I can think of, and this is the truth, is that we ENFPs are much stronger than we think we are. It's a societal trope that to feel deeply is to be weak, but I think in grounds us in a way that few others can understand. You are in the thick of the storm, and the squalls will keep coming, but the recovery has already started. It may not feel like it now, but you have to stop a moment and think about just how strong and decisive you have been in just posting and talking about this enormously difficult event in your life.
I understand what you mean when it comes to partners changing in the middle of things. I'm the middle of that myself, and I think that it's very common, generally, since people as a whole aren't static throughout their lives. What does happen, though, is that sometimes, people evolve away from each other. He needs something different now and it feels like he's blaming you somehow for not being those things. Maybe it comes from INTJs being so grounded in stability--they may not necessarily feel like they've changed all that much.
But that change? It feels like a frickin' BETRAYAL. You are both on the pitch and he is the one who has changed the ground rules, without telling you, and looks down on you for not knowing.
Relationships are each a very varied and different thing. And each and every one of us are poisoned by what we are told are "normal" relationships. We are poisoned by media, misled by family beliefs. A friend of mine and her husband amaze me: they are both polyamorous, have separate partners, but are in a deeply committed, lasting, and loving relationship with one another. It is the farthest thing from traditional I've seen in my life. But the constants in their relationship--the foundations--are openness and respect. There is no arrogance, no condescension, and when a misunderstanding does arise, it is treated with proper attention and a genuine drive to see it resolved.
Not only do we struggle to relate to our partners, we struggle vainly to fit our relationships into the tiny, weird-ass frames that we have been led to believe relationships should fit in.
Ultimately, though, you must do what is best for you. As an ENFP, it is enormously difficult to separate oneself from the feelings of others, but one of the best phrases I've ever heard from anyone is this: "I am not responsible for your feelings." If you have done your level best to be honest and respectful, and you feel that you're getting jerked around, you're not being respected, and it's simply time to you. You are the one who matters most. Always.
I wish you luck, patience, and perseverance. Keep us posted, and my thoughts are with you.