What am I doing wrong?? Or is he lazy???

My husband and I have been married 3 months, and well his sex drive has gone way down ! We did get pregnant by surprise in June of 2015. In the beginning of our relationship we couldn't keep our hands off eachother.. At the 1 year mark it all dropped off he told me he was not a very affectionate person. I felt jiped or lied to. But, we continued our relationship. I just dialed back my affections by 80%. Now 3 years later we got pregnant , moved our wedding date up. Unfortunately I miscarried. And almost passed away from blood loss on the OR table. It was devastating  and very upsetting and scary for him and I. Finally he has come around to want to try again. I hate to push the time frame and put pressure on him  but I am 34 years old i've been told by my doctors in the most blunt manner possible to "get on it " "Time is ticking "I feel excited when he is affectionate towards me! Plus the sex is still amazing... But we only have sex  once a week! During my ovulation cycle! He sounds excited about us having children. And even likes to point out differences in my behaviors health and or  body that I might be pregnant.. The doctor explained that I should get pregnant easier after miscarriage in a D&C yet for the last two months The stick has turned negative.. I know he's a mechanic and he works really hard. I work three jobs    And I go to college part time as well. Am I doing something wrong or is he just being lazy. I've gotten to the point where I openly ask him almost every other night are we going to try and have sex??? After being cute being coy and trying to seduce my husband.. I'm out of ideas and I'm really getting upset and frustrated about the whole thing! Any ideas anyone