There is much research into the affects of mood (particularly stress and depression) on Lupus. Most research has indicated that stress and depression can cause Lupus to worsen (flare-up). So, it is quite plausible that your bi-polar moods would affect the disposition of your Lupus. I've read almost nothing about Lupus aggravating bi-polar moods, but it is not out of the realm of possibility. So, you and your husband may be right!
Peace and Blessings
Look For The Good and Praise It!