One of the major plot points in the first season of GLOW is the big reveal that Ruth is having an affair with Debbie's husband, Mark. We find out they've had sex on multiple occasions, and Debbie finds out at the very end of the first episode, sparking a very real fist fight between the two women. The fight inspires Sam to hire Debbie as his lead actress. Throughout the season it's made very clear that Ruth had been in a rough spot in her life and has absolutely no feelings for Mark. It's made even more abundantly clear when Ruth finds out she's pregnant and Sam takes her to get an abortion. This is guaranteed to come out in season two, so remember it!
