- "We shared a few milestones together. First beer, prom, sex."
- ―Tess to Rachel Zane
Tess and Mike Ross have known each other since they were seven. Growing up together, the pair were very close, eventually becoming romantically involved with each other. They have also decided then that they would break up at the end of summer before college because Tess will be going away, but Tess never showed up to their last meeting, fearing that she might not be able to say goodbye.
In 2012, after being overwhelmed by the recent death of his grandmother, reunites with Tess at her wake. Later, the duo return to pack things up from Edith's apartment. After Mike kisses her forehead, the pair begin to make out until Tess reveals that she is married. Mike promptly orders her to leave. However, he later calls her to his apartment, not caring that she is married, and engages in a sexual relationship with her, which is eventually discovered by Rachel Zane. In the aftermath of his case with Liam Colson, Mike calls their relationship disgusting and cuts ties with Tess, although she reveals that she doesn't love her husband and implies that she is willing to end the marriage to be with Mike; Mike, however, asks her to leave.
Following the end of their affair, Tess returned home, where she notified her husband that she had slept with Mike. Her husband then proceeded to ambush and assault Mike outside the Pearson Hardman building.