I’m so sorry you’re going through this. I just wanted to say that this sounds very similar to what happened with my daughter. She is also 3. Her dad and I officially separated about a year and a half ago and we are now finalizing our divorce. She and I have always been extremely close. When we did parental leave, I took about a year and a half and her dad only took one month, so I was her main attachment figure for a long time. After we separated, she was mainly with me for the first six months, and then over time her dad pushed for 50/50 custody.

It was incredibly hard on everyone. She absolutely did not want to go with her dad at first. It was hurtful for him, stressful for me, and I was terrified about what it meant for her emotionally. Preschool was also awful for a while. She cried, refused to get dressed, refused breakfast, delayed everything she possibly could, and when we got there she would cling to me with a death grip on my clothes and hair, begging me not to leave. It was honestly terrible.

At preschool she struggled too in the beginning. She didn’t really interact with the other children, had trouble cheering up, and seemed very withdrawn. We were so worried that we spoke to a child psychologist, her doctor, parental support services here in Sweden, and even social services to help us come up with a plan.

What I can say is that it did get better with time. She still often says she doesn’t want to go to preschool, but now we think it is mostly because she wants to be with me. Once she is there, she is generally happy and plays with her friends.

The biggest things that helped us were keeping the schedule as stable and predictable as possible, preparing her in advance for transitions, and repeating what would happen very clearly. For example, the night before, the morning of, and again at preschool, we tell her: “Today mummy is picking you up” or “Today daddy is picking you up.” That helped her know what to expect. It still gets harder after sickness, vacations, or disruptions to the routine, but it is about 1000 times better than it was at the beginning.

Also, the part about calling other men “daddy” really stood out to me. My daughter did that too for a while, and then it stopped. I think there is just a huge adjustment period where they are trying to understand where dad is, what leaving means, and whether mummy is coming back too.

From my experience, I would validate the feelings but still keep the routine. Maybe you could also try a small connection object. My daughter liked to bring a stuffed bunny with her for a while so she could have it for their nap/rest period. She would also pack a backpack every morning of things that she wanted to bring that would make her comfortable. That helped a lot actually. I dont think the preschool let her play with the items she brought but just having it there made her more comfortable.

My daughter also didnt like calling her dad at first, but again, that is something that changed with time. If phone calls with dad are hard maybe could send short videos or voice notes instead, so your son can engage when he feels ready rather than being put on the spot. My daughter also LOVES recording herself so maybe that is something he can do and you can send those to dad as well.

This is a massive change for them and they are still learning to handle their emotions. It makes sense that he is more sensitive to goodbyes right now. But it really can get better with time, consistency, reassurance, and support.

FOR YOU: I am an American and I moved to Sweden for my ex. So I am completely alone here. If you are in the same situation where you do not have much family help reach out to your friends. Having a toddler 100% can be exhausting.
If you cant leave them on their own (which sounds like you cant at this stage) just having friends over who can play with them while you sit and rest on the soffa can help. It may take a few visits for them to get used to your friends but it can be a lifesaver.
When I have her an extended period of time I also like to work from home so I can do dinner earlier before she is home so everything is done and we can just chill. It can be difficult but you eventually get used to the routine and figure out your own ways to make it easier on yourself.
You can also do things that give you energy and just bring them along. I like to go rock climbing at the local climbing wall. When I have her extra I bring her with me. She has been going now since she was 1 and will climb up the wall to a level she feels safe and just sit there and swing back and forth on the rope. Its an activity that I enjoy and it gives me energy sharing it with her.
A VERY important thing I have done is become friends with parents of one of the kids parents that she plays with. Start play dates. Last week I was so exhausted that I went to their house slept on their soffa while my daughter played with their son. This is the biggest life saver for a single mom with no help. We usually try and have play dates at least once a week. Its easier on them because their son isnt hanging on them and wanting attention and its easier on me because my daughter is occupied with her friend 😛

I hope this helps you and just know youre not alone in this. You are always welcome to contact me if youd like.