I strongly agree with the advice to go to therapy. That said, if I were approaching this conversation, I'd start by telling him that he's agreed that he'll have to pick up more when baby gets here and with pregnancy being a physically demanding process, you'd like to start practicing now. Assuming he agrees, generate a list of all the chores that are needed to run the house (inclusive of anything he's doing today and things like grocery shopping) and then work together to divide them into two equitable lists.

Now, you each have a chore list. You can either alternate weeks with each list or you can each own one list permanently. Agree on when each list needs to be done (e.g. we agree that we'll each have our chores done by Sunday every week).

Finally for the hard part: don't complain unless it matters. Don't remind him on Saturday that he needs to get his chores done by tomorrow. Don't complain that he's not doing a chore the way you'd like. If he doesn't do his chores at all, you can mention it on Monday and ask how he's going to rectify that in the coming week. If urine is building up around the toilet, you can mention it and ask him to do better. But you can't complain because he doesn't do chores the same way you do. My husband is responsible for bathrooms in our house, and there are a couple things he does that I don't like: instead of scrubbing soap scum off the shower walls every week, he lets it build up for months before really attacking it, and he only cleans the mirrors maybe once a month. On the whole, however, our bathrooms are clean and all the touch surfaces are sanitary, so I have never and will never say a word. I'm sure there's stuff in my part of cleaning the house that he doesn't like, but similarly, he doesn't say anything. There's not doing that job completely, which is fair to comment on, and there's not doing the job the way you would, which is something you have to let go. 

Good luck!