Me, personally, no. Too much baggage with MY ex of 30 years. Zero sexual attraction, and the sex was nil near the end anyway. I had a running affair with myself for half of the marriage. Needless to say, I didn't feel run back to her to scratch an itch.
Having sex with an ex MIGHT leave an impression with your next significant other … even though the past is out of reach, one DOES have some control over the present -- and the present becomes the past soon enough.
My new wife had sex with her ex not that long before she met me. She shared this before we had any intention of becoming partners (we were in the infamous insisting-we-should-be-just-friends-it's-too-soon-after-divorce-tell-ALL timeframe. And, we told ALL. ). There was, apparently, a strong physical attraction/friends with benefits thing that persisted with her ex despite a history of infidelity on his part, even after they hooked up again. She said she accepted him for what he was. He just wasn't a good husband. For my part, I was no angel. I shared that I had had sex with well over a dozen women before my first marriage, sometimes rather casual hookups during a time I was dating several women. This was in the pre-AIDS era, there was a LOT of casual interactions and there was a very strong acceptance of friends-with-benefits in my social groups. I remained faithful to my ex wife until the end, but came to my new marriage with an admitted history of casual sex, though long in the past. I had remained chaste after my divorce, and really had no intent of getting into any relationship for quite a while. Of course, that kind of thinking leads to a rapid falling in love.
All this aside, the knowledge that she DID succumb to sex with her ex pops into my mind at times of self-doubt, despite all efforts to put things in context.