How do I stop this feeling?

Im so broody for another child, i have an 18mth old and i love him to bits just really wnat a brother or sister for him, my partner says he doesnt want anymore at least not now, his sister has just had a baby too and the feeling i had when i held him i was so determined that i do want another, its all i think about, i already have a kitten if anyone thinks that would help. Is there anything i can do to help rid this feeling at least for now until my partner is ready?