Frustrated. Long post. I need HELP!

Me and my husband have been TTC for about 19 months total. In December of 2015 we found out we were expecting, and unfortunately it ended in a MC on 02.02.16. Since then, all he talks about is wanting to be a dad and wanting me to get pregnant again, yet he always avoids sex during my fertile Windows?! I've asked him what the deal is, if he's sure he wants to try again so soon, etc and he just says he doesn't think about doing it. I've tried dressing up in his favorite lingerie, doing all the little things that turn him on, showering with him, everything I could basically think of.. And he just shuts it down everytime. I just keep hitting a brick wall. I feel like our marriage is failing, and I've told him this but he doesn't act like its a big deal. Sex is a huge part of a relationship is it not? What do I do 😭😩