The erection issues and low drive were already there before pregnancy, so it does sound like something worth looking into properly together, not just reassuring words. It might help to gently suggest he sees a doctor, because sometimes it is a physical thing that can actually be treated, and having that conversation framed around his health rather than your insecurity can take some pressure off both of you. You are almost at the finish line with your pregnancy, so once things settle after delivery, it could be a good time to revisit this together with more headspace, maybe even consider couples counselling if the communication keeps going in circles.