Thanks everyone for the encouragement to tell him, i knew i had to i was more wondering how...

I called him yesterday and asked if we could have a talk, a talk that was "safe" so to speak (non BDSM) as we do this from time to time about things that really have to be discussed that are a bit hard to discuss and keep in role.

So he came over and we talked. As soon as i told him, he told me two things: 1. He already knew (at least was 99%) that i was pregnant or that i was worried i may be. 2. He wasn't angry about my being pregnant, we are two adults having sex and obviously there is a chance even if i don't miss my pill.
He wasn't even mad i missed the pill, he was however very hurt that i didn't tell him and then that i was deceptive with the rest of it..
So as much as i will be punished for lying (yes, harshly but not physically. we both want to be cautious as we make up our minds what to do) i feel so much better that he knows.

My biggest fear was that this would (or still will) change my position in relation to him, i don't want him to think that i cannot be submissive and pregnant. It's so much a part of who we are i am afraid of the damage it would do to try and get out of our roles...
any advice on that side of things?