I think pregnant women can be seen as very fragile, and of course if you're having difficulties it's important to be mindful of them. But my body is still my body, and I want to enjoy it, now and after childbirth. Even down to things like when we're in bed, even if we're not doing anything but laying in bed, I try and still cuddle DH and stroke his back or whatever, and not make everything about the baby or my pregnant body (sometimes tricky with an enormous u-shaped pillow in the bed too, which DH has named Ursula! 😂)
It obviously depends entirely on your relationship with each other, yourselves, and sex generally, but I think masturbation can be an important way of both partners achieving a sense of release or satisfaction during pregnancy even if the other person doesn't feel comfortable having sex or doing other things. I've let DH know, as I hope he always knows, that it's fine if he wants to do that, it's not an affront to me or our sex life.
On an entirely different note, baby booted me right in the middle of the stomach last night, totally out of the blue, and then nothing! 😂 Just a reminder that he/she was still there I guess.