viki,
IMO it doesn't matter if sex is work or play. IMO work and play is defined in scripture as the same. To toil, to work, to play is all the same. We were given this earth to enjoy things. To make, build, and grow things. This is what we were told not to do on the sabbath. Are you not creating or growing life by having sex? The problem is we have turned it into a tax, fee, and interest paying society which causes feast or famine. We have rich and poor. Just who is poor? The majority of course, and some don't even realize it. You can make $100,000 plus a year, but if you are working and not enjoying it then you are poor! You are a slave to the system. The elite or the system has separated work from enjoyment! This is why we have so many problems with separation. When you have separation you have disagreement, rebellion, and turmoil.
IMO the answer to the question isn't asking yourself if you are working at it, but if you enjoy it. If you are not enjoying sex with your spouse then look to yourself before you look to your mate for the answer.
That should answer the question IMO of course. Search yourself for your own answers, but I am trying not to play the guitar on the sabbath because I enjoy it.
I am still learning myself between right and wrong, and by no means perfect.
The lesson for denying yourself from enjoyment...so you know what it is to be satisfied. To not be satisfied leads to greed and corruption. Like I said I am still learning.
Peeblers do it on other boards!