You didn't go into a lot of details of the conversation. But since it was a "forklift' place, is there any chance he was there on business????? Or do you know this other hussy? He must know you have caller ID, Hell, who DOESN'T??? There is no way he would call you to talk, if he knew you were going to see the caller ID from a woman he was seeing?????
Although I will admit that my W e-mailed me one time from her BF's screen name! Since she had been living with him for quite a while, I didn't go into shock, but your situation is different. Has he called to try to explain?????