I think your comment "he's not the full quid" says a lot. It was a full shilling in my day ... old gimmer wises up to inflation
) The reason why there are now so many Web articles about identifying personality disorders is exactly this feeling of yours. People around the disordered person know there's something wrong - is "not as others" but it's hard to put your finger on, thanks in part to all the bluster and chiefly to the disordered person's dedication to appearing 'normal'.
It's helpful, I find, to accept that the person has PD. Almost all the emotional agony is caused by dissonance between what this person believes about themselves, and what we observe over time. Obviously we fall in love with the construct, not the real being. That leads towards self-deception, because it's painful to admit we were hoodwinked into backing a loser. On top of that, all our social conditioning presses us to treat other people considerately. This presupposes that other people are fully functional, emotionally rounded human beings. A proportion of them are not.
Some posters will jump on me (and perhaps you) for making an amateur diagnosis. The important point is that this diagnosis helps you to understand what's happening, and offers the detachment necessary to proceed with saving yourself & your children.
In case this helps you: As grounds for a divorce, the unreasonable behaviours cited must have happened within the past six months. They don't need to be massively dreadful, simply behaviours that make it impossible for you to live as this man's wife. People have successfully divorced over disagreements about what to have for dinner, and snoring.
I served papers on XH2 knowing he'd refuse to sign, so I made my complaints pretty embarrassing by his standards. As I expected, he flipped his lid over my petition and said he'd suffered more than me. I suggested he do the petition, then - and sent him a fresh set of forms to fill in.
You'll know how your H is likely to react. If the answer is "violently" and/or that he will try to contest the divorce legally, make preparations to protect yourself.