Aiyoh, I totally understand your worry! Honestly, I think it's okay to fulfil cravings sometimes, pregnancy is already so tough, and a little indulgence won't spoil them, but you also don't need to say yes to everything, you know. I try to give my kids what they ask for maybe 70-80% of the time, and gently explain the other times why we're having something different instead, so they learn that not every want needs to be a yes. The key is balance lah, fulfill the genuine cravings but also help them understand boundaries, so later on they don't expect the whole world to bend for them.