It was difficult when they were babies and toddlers. We Attachment Parent
and my time was very scarce. We still had sex, probably more than most people do when they don't even have kids, but it was less for us than we were used to. When our kids start sleeping better at around two years old, it gets better.
When they are more independent it gets even better in the sex department. My Man and I then have more time for each other when our kids are more independent and are less likely to walk in. (Even though they learned when they were toddlers that you always knock on a closed door before coming in.)
We have one moved out, and two living with us. One in Grad school and one in Middle School. About 2 years ago, we moved the middle school kid (who was in grade school then) from the room across from ours to down the hall. We have more privacy now and we have a spare room across from us where no one sleeps. I feel better being louder when there isn't a kid only 10 feet away.