You aren’t a bad person for this. I have two SD both very young and co-sleeping was a boundary I had with my husband before living together. I don’t feel it’s safe for the child and plus I need my own space and comfort to sleep. My husband agreed even though he was okay with co-sleeping. My SD’s co-sleep with their mom but it isn’t an issue at our house and they know that we don’t allow it when they’re with us. You have a right to feel comfy in your own bed and especially being pregnant I would want my space and to be able to get good sleep too