Yes, you need it! Constraining and scheduling your sex drive around conception schedules is really tiring and often highly non erotic- so I am totally sympathetic.
The first thing you have to do is have some "off the clock" sex. Do it at the "wrong" time-and just enjoy yourself. Anything , even sex, can start to feel like work if its on a schedule. You need to have sex together sometimes just for " fun"-even if you couldn't possibly get pregnant during that time. The point is to make love to each other- not always have sex as a utilitarian function.
Second, put more play in your relaitonship. Use Fantasy- a lot! Weave erotic stories into your relationship and that will definitely spice things up. He can talk to you- or you can talk to him and take on new personnas -just for that particular love making session. Pretend he is the first man you have ever slept with- or if he was- maybe a man who is a perfect stranger who you seduce. Let him pretend you are an his employer and he is your limo driver. Or pretend he is a rock star and you are his groupie. You get the idea, take things that are edgy, create new identities and have fun acting them out.
The point is that if life is all the same sort of thing these days- work to make it different. Dress up and go to dinner without your panties on and see if he can find a hidden way to actually touch you-- go make love in a bathroom at a nice restaurant without causing a ruckuss.. buy some vibrating panties they sell in sex stores that are activated by remote control switches! ( a lot of fun!) Play with each other and make each other laugh. It will be good for your sex life, marriage and perhaps even your fertility.
what might help is location location is everything. Go for a walk, do something spontanous, new location,postitions, so forworth it will make it feel more like fun then feel like work