Hi, just to chip in. I think the internal/external MLC is spot on - and perhaps instead of dealing with it, the MLC can go 'external' as Mirage suggests.
I would agree that many, including my xh, have an internal MLC before it goes external. Perhaps there is a point at which they either decide to deal with it themselves, or externalise it onto others. My xh was so very very mean for a long time. That seems to have largely stopped, but I am not sure whether it is just that we all have very little to do with him, and don't see it, or whether he is now less angry. I get a sense that he is still a slumbering volcano!! But I hope he is less agnry.
Trouble is, once they have externalised the crisis it feels as if all restraints are off, and everything comes pouring out. They are then like a child who has had an enormous tantrum, and doesn't know what to do next. They lack the resources to sort things out [if they had the resources they wouldn;t have had a MLC] and so many of them remain stuck, with some awful OP who encourages all the most destructive parts of the personality.
They seem to choose an OP who plays to the shadow part of them . . . .