Via a sperm donor or via another person who wanted to co-parent with you without displacing your husband... it wouldn't be a "traditional family" model, but its by no means impossible, especially in poly!
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.