A woman, who WOULD NOT identify herself called our home phone saying that "she really needed to talk to my...?

husband. (She called him by his name.) He wasn't home from work yet and I asked if she wanted to leave a message. She just kept saying that she really needed to talk to him. Then she asked who I was and hung up on me when I said I was his wife. In the months following that call we have received several anonymous calls. One evening the caller evidently forgot to *67 and I got a number on the caller ID. Unfortunately, I've been unable to find out who the caller was. Two questions: would you think my husband was definately cheating and does anyone know how to find out 'who' a number belongs to? I've tried all the reverse phone call websites to no avail. Please help! I need concrete proof!