Trich

So my bf tested positive for Trichomoniasis not long ago but we have been together for over a year now. I had a urine sample done because I was pregnant back in June and tested negative. I don’t know what to do… did he cheat? Did my results just give a false negative? Did he catch it from something else (I read you can catch it from towels/toilet seats)? He swears he didn’t cheat but I just don’t know. He doesn’t really have time to cheat unless it’s at work or going to/from work, any other time he is with me.