Spicing things up and renewing the 'spark'?

The last few months, my boyfriend and I haven't been having the best sex. It started when I started getting big and uncomfortable (currently 7 months pregnant), and I don't know what we can do to rekindle the romance. Usually sex is just grabbing the lube and doing it doggy because it's the only position that works these days. He won't go down on me anymore because of the thick, excessive vaginal fluid I've gotten. (Just from pregnancy! Not an infection or anything) so I haven't been doing much for him either. Because there's no more closeness in our sex, we don't cuddle after or feel that special connection you usually get afterwards. How can we spice it up so that we regain our passion and have fun again? I hate that it feels so awkward and that we basically just do it out of obligation to each other these days.