Struggling with Separation and Co-Parenting

going through a separation of my domestic partner/fiance. Even though I should have known it was coming, I was in shock and couldn't accept it. I just moved out and rented a room 5 minutes down the road. last night was my first night away. it doesn't feel right. We took in a boy when he was born and he is 4 now, he is my best friend and this co parenting and being away is breaking me down, along with not having her or a routine. I got so reliant in what was in the house and her cooking and just having ppl there (even if we were not super happy but just being there). We were always happy with our 4 year old and would laugh together when with him. she also has 3 older kids teens/adult.....I have this hope and it's just painful.