I have not seen it in my cresteds yet where the females lay infertile eggs just being around the males OR are triggered to do so with seasonal/ temperature changes. My leopard geckos used to do this and my female tokay has done this though. It would not surprise me if the cresteds did this. If your eggs are still pearly white after 5 days or so, chances are pretty good they are fertile. Commonly infertile eggs will be yellow or turn yellow.

The female cresteds do hold sperm. They start laying clutches in 2’s and lay up to 6-7 months sometimes. I have seen them lay in 2’s as early as 3 weeks apart and as late as 5 ½ weeks apart.

Good call on separating the two of them. I separate them if I know she is gravid and sometimes sooner if he is a little too rambunctious and she becomes reclusive.

Hope this helps.

Severa