Since the whole point of this structure (A ydy B) is to indicate an identity between A and B, surely this sentence can also mean "My husband is Owen"? In fact, isn't that more likely to be the case, since in identification sentences Welsh normally puts the important/new information of the left side of the equation, English on the right? (Prifddinas Cymru ydy Caerdydd = Cardiff is the capital of Wales) versus (Caerdydd ydy prifddinas Cymru = The capital of Wales is Cardiff).
Yes, but there you're talking about focused rather than identification sentences (even though those happen to be identification sentences too).
In focused sentences the element that is being focused upon comes at the head of the Welsh sentence, and does so even in non-identification sentences.
Thus, Ar y bwrdd mae dy frecwast (di) = Your breakfast's on the table. (Here I have used bold to indicate the emphatic intonation that is used in English).