All of Elric's official wives let Airisa be rather possessive of his little dragon making potion at night, all willingly accepting her company during what should have been their alone time with their husband for a few days. None of them were actively trying to get pregnant, so if it helped her understand that fire was the the seed of creation and destruction it was fine.
They did remind her that she had responsibilities towards a little boy she had been given, when she tried to follow Elric to the main branch hall of the Explorer's Guild in New Vlantis, like she was his pet human. In a way she was, but that did not stop them from telling her to go nurse Gladius and study dusty old spell books while Elric was occupied with other matters.