Is my girlfriend (28f) cheating on me (31m) with her coworker (27m) when she comes back home at the same time he gets off work every day?

I work as an in home repairman, I work my own schedule so I can be there when my girlfriend (28f) gets home from work and I also work weekends so I can have days off to run errands, mow the lawn, etc. So, I come home early every morning before she leaves for work and leave late in the afternoon when she gets home. She’s been working for this company for over a year and never really comes home in the same clothes she went to work in before this guy (27m) started working there 6 months ago. <br><br>When she comes home she’s always sweaty, smells like dirt, has dust on her, etc. I don’t get it. I know it’s not her job, she works in an insurance office. The last time she came home she had a large mud smudge on her hand that I went as far as to ask her where it came from and she said she didn’t know. When I pushed more she admitted it was probably from the day before, but she doesn’t remember wading through a muddy area. That was 2 days ago and today she came home with the same type of dirt on her feet and ankles, and the same smell. <br><br>Now the concerning part is that she comes home at 4:30 every day he gets off at 4:30. It’s not a team that goes out to a site or anything, they’re individual offices. If there’s an emergency they’ll come out to the house but usually they’ll just schedule another day. The reason I notice is because I work close to where they do so when I head to my appointments I notice if their cars are there. Sometimes he’s already gone when she gets there, but more than not he’s still there. I don’t think she would ever cheat on me, and that’s what keeps me from calling her and yelling, because I know she wouldn’t. But the weird timing and the fact that she’s changed in the last 6 months is getting to me. <br><br>Should I trust my gut and bring it up to her?