Why would he do this?

I used to mess around with a married man about 5 months ago but we dont talk anymore. We go to the same gym to play racquetball and thats where we see each other still. I still have feelings for him but we never ever talk and he acts like he dont like me anymore when I try to say hi to him but then he will give me flirty looks. Yesterday, I went to play racquetball w/my sister and he was there and we ended up leaving the gym at the same time. Well I went with my sister somewhere when we left and we were stopped at a stop sign that was in the parking lot of the gym and he went to the next street over and was stopped at another stop sign but we could see the front end of his car. Well he always goes right and he had all the chances to turn when traffic was clear, but he sat there waiting to see which way we would turn and when he saw that we went left, he bolted out of the street onto the road and sped up really fast behind us. Why do u think he would do that? I really dont understand.