People have kids when have diabetes (high risk of birth defects), cancer, MS, just about all the diseases under the sun. There are psychotropic drugs that are very safe in pregnancy and breastfeeding, more so than the drugs for other illnesses.

It's entirely between you and your hubby, but I for one will not be judging you for having more kids if you so wish. Since you already have bipolar you would be uniquely able to support your child if they too have it (remember, they are more likely to NOT have it). Taking advice from one who knows is a hell of a lot easier that getting a lecture from someone who really doesn't get that bipolar people deserve a normal social life, work life, family life, just like everyone else.

Hugs