Not having enough sex since we had a baby

Hey FTM here and we had our baby girls May 2020 last year at 23 weeks. Our angel baby twin A went to heaven after 13 days and Twin B fought for three long months before she came home .... our miracle baby is doing GREAT!!! Anyway while I was pregnant we didn’t have sex.... barely had sex while baby girl was in the hospital ( we were both very stressed out ) well our little girl is 10 months and on a schedule.... we are having sex maybe 3 times a month and it is driving me nuts.... I stay home with our daughter and I’m not as tired but I have my days.... this is making me feel insecure and sad ..... I don’t understand how we went from having sex at least 15 times a month to maybe 3.... I tried talking to my husband about it and I got the excuse I’m tired ( I told him that’s crap he never initiates ) doesn’t help he sleeps in another room but the baby is finally in her crib .... wtf !!! I’m worried about our marriage