Tired of it

I'm tired of "doing it" on a schedule. My husband and I used to enjoy spontaneous, fun sex! Now it's so mechanical and vanilla... I love him with all my heart and soul but two miscarriages in a years time has dampened our enthusiasm and we are desperate for a child. Heartbroken and desperate aren't very good emotions during sex, ya know?!
Any ideas? I wanna liven things up and have some spark again in the bedroom! I'm tired of boring timed sex after long days at work....