Well he could have given you the blood test to see if you are. My husband had a vasectomy right after our daughter was born years ago. He did the labs and had a zero count. I started feeling sick all of the time and he suggested a home pregnancy test. I knew I couldn't possibly be pregnant but I took one just to prove him wrong. He read the results and I thought that he was messing with me. I went into the doctor they did a urine test which also came back positive. I told them that there had to be something else wrong as hubby had the vas, and I was not sleeping with anyone else. My doctor drew the blood and we waited like 20 minutes to get the result. It was positive.

So yeah, I'd be angry too. The test is fast and simple, there's no reason that he couldn't have done it while you were there to put your mind at ease.