That makes a lot of sense.

He's even told me that he wants to go 6-12 months without an argument to feel secure in this relationship. That is totally ridiculous to me - it just doesn't seem possible, or even wise. I want to be totally open with my partner and not hiding topics away if I know we will disagree. I don't want to feel like we're doing training-wheels-relationship. I want security at this point.

Your last point, that she sees the disagreement as normal and a way to learn about each other, is something that I agree with. Oftentimes I'm surprised to hear that he felt we had an "argument" which to me felt like a conversation.

The other point you made,that to you it felt relationship ending, is something else that I feel too. Oftentimes a disagreement will happen and he'll want space and time alone - to me that feels like he's breaking up with me and sometimes he does insinuate that this could be the end. I feel like he's going to breakup with me whenever we disagree and I speak up.