It looks like MM said "they" were going to have a baby, but didn't explain further. I wouldn't take it as a given necessarily that they don't know the paternity of the child and don't plan to find out... the phrasing is open to interpretation.
Me, 30ish bi female, been doing solo poly for roughly 5 years. Gia, Clay, and Pike, my partners. Davis, ex/friend/"it's complicated." Eric, Gia's husband. Bee, Gia and Eric's toddler.