We've been together a long time, more than 20 years. It's changed depending on what our priorities were. When we had small babies or I was pregnant and on bedrest, it was less frequent; about 3-4 times a week. Now, with kids older and our intentionally dedicating more time to our sex lives, we have sex between about 5 and 12 times a week. We go in spurts; sex Thursday night, Friday Morning, Friday night, Sat Night, Sunday morning, then take a break Monday and half of Tuesday. Then pick up on Wednesday again etc. (Just an example, it isn't always like this exactly.) We tend to have marathons that stop when we fall asleep and pick up the next morning. I count those as two, I guess.
If we go more than 2 days without sex we both get irritable and start sniping at each other. It eases a lot of tension (we're both intense people) and helps us relax and bond better. We both need a lot of it.