I wonder if the three of you can take part in family counseling? Or if you and your son can do some counseling?
Can you arrange some more one-on-one time with your son?
On the one hand, your son needs to know that he is the most important thing in your life. On the other hand, he also needs to learn appropriate boundaries and taking responsibility.
Some of the most unhealthy and dysfunctional people I've met were the ones who were "catered to" as children - always getting their way, never learning to take personal responsibility, etc. While you may think you are loving your child when you give him everything he wants when he wants it, in actuality you are doing him a dis-service.
If your son were an infant, I'd tell you you are insane to be dating. When they are babies, they need to be the center of your world. But if your son is at least pre-school age, in the normal course of events, he would be going to pre-school.
So that is old enough to understand limits.
For example, by the time I was 5 years old, I was expected to play quietly by myself for a half hour each day while my mom took a nap. She was a very devoted mother but she also taught my brother and myself that adults also have needs and as we got older, we became more independent and able to care for ourselves. Unsurprisingly, there is almost no friction in my relationship with my mother now. There is mutual respect as well as love.
You need to figure out if there are things your son needs that he is not getting, and find ways to accommodate him. For example, maybe he needs more one-on-one time with you. Maybe he needs you and your bf to allow him to choose an activity for the three of you to participate in.
But your son, if he is at least old enough to be in preschool, is also old enough to understand that other people also have needs. It's OK to let him know that while he is the most important person in your life, he is not the ONLY important person in your life, just like, hopefully, you are not the only important person in his life. Hopefully he also has friends, grandparents, a father, etc. Maybe encourage him to also spend more time with the important people in his life, via Zoom if that is the only safe option.