It is hard for us to understand why, even with all the encouragement and support that we give our spouses they continue tho have their self doubts. They continue to second guess even if we are explicit about our desires and that is hard to change. Part of his reluctance is your growing belly, thinking that he may harm the baby. I don't know why people freak out about having sex when you are pregnent. Unless it's extraordinarily strenuous, it should not be a problem. You can always stop if there is discomfort.
Hugs to you about the biopsy and wishing you well with the results. It is hard waiting, but you are being proactive about it and that is positive. BC also runs strongly in my family and I know how that makes me feel. I have annual mammograms and do a breast check often, so I am doing what I can, too.