At the wedding of his sister Catharina and the painter Simon de Vos in 1628, he met Constancia van Nieulandt (or 'van Nieuwlandt'), the 17-year-old daughter of the painter and poet Willem van Nieulandt II. The following year van Utrecht married Constancia. The couple had 13 children. Constantia became a painter and poet in her own right. She is believed to have shared the work in her husband's studio and may have painted partial or entire copies and variations of her husband's work. A still life with fruit fully signed by Constancia van Utrecht and dated 1647 is entirely in the manner of her husband.