There's no guarantee that any child you'd have would develop either mental health issue. Or if they did, the bipolar disorder, in particular, may not show itself until their teenage years, or even 20s, or so. You and your husband would clearly understand some signs, and if you both take good care to manage your illnesses (successes or fails), hopefully you'd be quick to do the same for a child. Though perhaps not, it's also possible that any child would have a milder course to their illness.

If you and your husband are struggling, greatly, in your lives, it is worth considering if you can add more responsibilities. Also, are you at a stage in stability where medications might be reduced, or modified? Pregnancy might require some change(s) for safety sake, for a pregnancy. A long talk about this with your psychiatrist and therapist would be helpful with this. Also, do you have anyone that could help out, if you and/or your husband can't manage?

Clearly you seem to want a child. Or think you may. At 38 years old, the clock is sadly ticking to make a decision on this. I, on the other hand, never had a burning desire to have a child. Neither did my husband. In the end, we never had children, and do not regret it or have any feeling of "loss" because of it. If you truly think you will, then the talks with your psychiatrists AND gynecologist are in order. I wouldn't rush to a pregnancy without these talks. Certainly they would be the first step to the major responsibility you'd have towards a future child.