How do you all say no in a nice manner when rejecting your spouse request for sex?

Well it depends if you are rejecting him due to a short-term thing or is it like post natal not gonna have sex for 3-4 months thing. If it's the first, I would string him along and leave him with blue balls n promise him satisfaction over the weekend. Think, "baby, i can't wait to ravish your body this weekend. I'm gonna sleep in tonight so we can have a crazy animalistic good time this weekend." The second situation needs frank honesty and also a timeline, so something like, "baby, I love you like CRAAAAZY. But this whole motherhood thing has killed my mood - and I don't think we will be having sex for at least 4-6 months. I am so sorry. I know you're disappointed and so am I, but I am honestly way too exhausted and in pain to think of doing the nasty with you. I know you understand and I love you so much for being my pillar of support."