Let's get this important issue straight. In an ideal world, you're absolutely right, there should be compromise in the bedroom just as there should be a compromise in every other aspect of a relationship. But because we are living in the real world and this is a temporary situation, to force the issue of him not finding your pregnant belly attractive by insisting he meet your needs could be very damaging to your relationship.
No one should be forced into sexual activity that actually turns them off because we all have our own likes and dislikes. By pressuring your partner to compromise on his sexual dislikes, you run the risk of turning him off from sex with you altogether and that is not helpful!
Therefore, my advice is that you shouldn't expect him to make love to you, but rather ask him to fondle you with his hands or use a vibrator to stimulate you to orgasm. You can also masturbate and pleasure yourself — pregnant or not.