I wouldn't stress too much about him being mad or upset. We were not planning any more children, and my husband even went for a vasectomy... two months later I found out I was pregnant... I won't lie... I was scared to tell him. But on the other side of it, I really had no reason to worry. it's not all MY fault, and he would never ever consider the idea that he didn't WANT our child.
Anywho.... my way wasn't very creative, but...
I told my husband by leaving the pregnancy test on his side of the sink in our bathroom... i knew that the minute he came home he would go upstairs and pick out the clothes for the next day and lay them on his sink and see it... i snuck upstairs after him and gave him puppy eyes - he hugged me and said "oh my goodness... we're never going to sleep again... so much for retiring early, huh?"
It is what it is and can't be undone now... Good luck to you! I cant wait to read how it went :)