Why?q

My husband and I are married for over 8 years now. We have gone through 4 miscarriages and so much more together. We both care for each other but there is no more a spark. We have sex like once a month may be and it’s like the same old thing. Nothing turns me on about him anymore and may be it’s the same for him. Anyone seen us thinks we are the perfect couple but it’s like a empty vase. Why or what do I do?