'The Furmula'

No I don't think so...although I did suspect an affair between them at first, but after the wife explained everything to Stella and the way the interaction between her and the crew chief in the hotel room was played out, I realized that like the CSI team I had probably misunderstood. Both the wife and the chief seemed genuinely worried about Santos' health and safety, that's why they both came up with the idea just to sabotage the car (I think) so Santo would be forced into retirement.
The wife seemed genuine to me, she really seemed to genuinely love and care about her husband and really worried about his health. And I can understand her concerns, I mean, Santos seemed like the sort of person who is so devoted to his job, he's the sort who would never give up what he loves doing until he is forced to the point that he absolutely cannot anymore. And what Santos does as a racing car driver is so dangerous, it was already implied in the episode that Santos had suffered many serious injuries to his health and body throughout his racing career, the wife has also said that she has seen her husband on life support so many times, I can't imagine the pain and suffering she went through witnessing her husband putting his life in danger time and time again, he just didn't seem like he knew how to quit racing. The wife and chief probably tried to persuade Santos to quit many times but he didn't listen to them. I suppose all the pain of watching Santos putting his life on the line for so many years really pushed her to the edge, she was desperate for Santos to quit racing, she felt she had to do something to force him to quit racing so he could finally take care of his health. And I think the chief felt the same way, he too seemed genuinly worried for Santos' health, so they both teamed up to come up with this plan. As far as their relationship goes, I think at most they were just friends and co-conspirators to this plot to sabotage Santos' career in a way just to get him to stop racing, but nothing romantic...at least they did not appear to behave romantically in any way to me. They did sort of hugged each other quite "affectionately" at the elevator as seen on the security camera, but that was it, that's hardly enough to suggest an affair. When Santos died they both seemed genuinely heartbroken and devastated, you could see it was never their intention to hurt him, they simply just wanted Santos to quit racing and start taking care of his health. The heartbreak the chief felt was so apparent in his rage when he angrily lashed out at the real perpetrator who sabotaged the car that caused Santos' death. And I think the wife was always with Santos by his bedside at the hospital, she never left his side, until he died of course. Her love for Santos and heartbreak over his death seemed very genuine to me. If she really was having an affair with the chief, I don't think she would've resorted to such drastic measures to try to force Santos to quit racing...I mean, think about it, if she loved Santos any less to have an affair with someone else, would she really care about Santos and his health enough to be that desperate in wanting him to quit racing? I think it's precisely because she loves Santos so deeply and worried about his health so much that she was so desperate in wanting him to stop racing.
Also, an affair between the wife and the chief would've given the pair more incentive to want Santos to CONTINUE racing, instead of quitting, because if Santos were to continue racing, that would've given the wife and the chief justified reason to see each other all the time, and that would've helped to conceal the affair from Santos and everyone else. For Santos to quit racing, that would mean he would spend more time with his wife and the wife would've stopped seeing the chief so frequently. So the fact that both the wife and the chief so desperately wanted Santos to quit racing, should be more proof that they were NOT having an affair.

So yeah, I think you're reading too much into it.

No they never had an affair.