I have not met my boyfriend's husband, 11 months in. The BF and I live in the same town; his husband lives in another state. I think if we all lived close, we would have met already. His husband visits our town every six weeks or so for a weekend or a few days and he goes there.
My BF's immediate family live in the area, but I have not met them either. His husband regularly accompanies him to his family events when he visits. I have expressed interest in meeting them, and my BF has said that it will happen.
My BF may be an extreme compartmentalizer; when he is with me, he does not text or call his husband, and when he is with his husband, he does not contact me unless I specifically ask for it. Any item of clothing or jewelry I may have left at his house is put away when his husband visits, and I have never seen any evidence of his husband when I am over.
He has expressed frustration with having to be compartmentalized in this way and that things would be much easier if we all lived closer so that he could divide his time between us (geographically speaking). I don't think his polyshipping style is an inclusive one. On the other hand, he has said that it would be "wonderful" if his husband and I could be friends. For my part, I am not yet in a place where I could walk into a venue and see him and his husband together in a couple-y way and be okay - but I'm a hardwired mono.