This is a retrospective one.
Myself and ex partner have been finished for several years now, but I saw him recently and it revived me thinking about the issue.
During the relationship he apparently rejoined a young Newfoundland dog his son had asked for when it was (I think) less than a year old or perhaps a year at the most after it opened its mouth over/around a child (in a buggy's) head.
When I say opened its mouth, i mean literally that - it didn't bite, nip, close it's jaws (though I suppose it may have had I not yanked it away). I felt at fault because I didn't realise it would do anything like that and had it in a loose lead, it turned it's head into the buggy and did that as we walked past.
He 'rehomed' it soon after, he said the new owners were ok with a visit so I asked continuously if we could visit but he refused to and said he felt too bad about it and couldn't. I didn't understand why, if he felt so bad, he wouldn't take the opportunity to check on the dog in its new home.j gave up asking after numerous attempts with the same response, but always felt uneasy about it.
I have since come to the conclusion, after the relationship finished and I discovered quite s lot of dishonesty and disingenuous-ness that he actually had the dog put down. If fits with the extremely black and white nature of his thinking (another thing that ended the relationship).
The dog had zero training (apart from the most minor stuff by his 12/13 year old son) and no canine company. It was a source of conflict between us because it was in the yard on its own a lot.
I've since read they're 'mouthy' and believe it was not aggressive in what it did (though I understand damage could still have been done).