The term "fancy" is misleading when so many responses take that to mean "want to jump each others bones 24/7".
I don't agree with a lot of these responses because, honestly, they're just too highly sexed.
My husband and I are in our 30's and have been together for over 6 years. We love each other, like each other and respect each other. We rarely argue and if we do it's usually because either of us is tired and/or stressed out about something (which we acknowledge later and apologise). We never call each other names. We do not have children yet but do have fur-babies (and he just sent me a text message to tell me he was thinking of getting them a Valentines present).
He is a good man. He believes in supporting his family. He doesn't drink or smoke, take drugs or watch pornography (and if he does, which he doesn't have time for honestly) at least he hides it well!).
All that said, I have a sleeping disorder so I'm tired a lot. It's getting better with treatment and I'm told my energy and sex drive should improve with time, but our lives dictate that we don't have sex every week. He gets really sleepy after sex and it "ruins" his night as he's too tired to do much. He'd prefer if we went to be and hour earlier but we're busy with work and other things sometimes that's just not possible!
So we have sex probably more like twice a month, sometimes possibly less. We've spoken about it and continue to speak about it from time to time. It's not a lack of want, it's a lack of time and energy. It's really cold right now and we're practically hibernating!
I do not equate the quality of our relationship with the amount of sex. I equate it to our level of intimacy, the want to spend time together, the enjoyment of that time together, and whether we're still attracted to each other.
So OP, to answer your question, in the beginning of our relationship were having sex a lot. As life progressed and the stresses that caused, it dropped off a bit.
As both you and your partner are happy with the status quo (and as long as you're talking about it so he knows he can talk to you about it if he needs to) then I wouldn't be worried.
I'm not indifferent to sex per se, I just don't think it's the be all and end all of our relationship. We get much more from our relationship than sex and it's just a part, and I don't think a major part either, not in the grand scheme. I wouldn't want to go without for the rest of my life for sure and I enjoy sex, so I'm not indifferent to it, I just know that other things in life are sometimes, not always, more important...