Yeah, I'd feel a little funny about it, though otoh, maybe they didn't want to jinx the process by telling anyone about ttc (trying to concieve). But, since an infant in the mix will impact not just them, but their 2 lovers, I'd say they made an error that needs to be addressed. Poly is complicated and kids complicate it more. Your bf will be way less available with a newborn/teething infant and broken nights' sleep, etc.
I think sometimes poly people can act like they are single or mono, and go ahead and do certain things, not fully being aware of how what they do with one partner ALWAYS ripples down to the other partner(s).
Love withers under constraint; its very essence is liberty. It is compatible neither with envy, jealousy or fear. It is there most pure, perfect and unlimited when its votaries live in confidence, equality and unreserve. -- Shelley
me: Mags, 59, living with:
miss pixi, 37