I feel for you...I love my husband and want to grow old with him by my side but our sex drives are drastically mismatched. Having a boyfriend with a higher sex drive than mine has really helped me see things from his perspective.
I used to be able to have NSA sex with friends and casual hookups but my poly experiences have not turned out that way. Fact is, feelings HAPPEN, so I would advise against promising that you will never develop feelings for these "casual" hook-ups. That being said, if you are sure that you are only up for sex but not emotions, you might get better advise on a swinging board rather than a poly board...
Me: poly bi female, in an "open-but-not-looking" Vee-plus with -
MrS: hetero polyflexible male, live-in husband (23+ yrs)
Dude: hetero poly male, live-in boyfriend (4+ yrs) and MrS's best friend
Lotus: poly bi married female, "it's complicated" relationships with Dude/JaneQ/MrS (1+ years)
+ "others" = FBs, FWBs, lover-friends, platonic G/BFs, boytoys, etc.
My poly blogs here:
The Journey of JaneQSmythe
The Notebook of JaneQSmythe