OP, my DS was 4 when he met my partner. We had been seeing each other for over a year at that point. Basically I'd been very slowly evaluating this man, giving him many chances to get frustrated with me, with not being put first, etc before I'd introduce him to a child of that age. 4 is a baby. So vulnerable. I wasn't letting a strange man near my boy until I had seen a lot of proof of good character.
If my partner had ever said a word about not wanting to be around a child again, about his ex begging him back, etc he'd have been so quickly out the door. Those are massive red flags, you want a man with respect, patience, compassion, understanding and the maturity to expect he will not be put first when he has stepchildren... you want a man who has a "servant heart", as it were. Again, you are talking about such a very young child here. You can't risk selfishness, a judgemental nature, or a man who decides that a child needs a harsh hand... that is poison and can so quickly escalate into violence.... it's very sad but it's true.
After my partner met my 4 yo, he'd stay over maybe once a week while DC was at mine. That lasted a year. Perhaps by end of year it was twice a week. During this time we started having short holidays. Again I was very watchful. I wasn't trying to "be a family", on the contrary I was auditioning this man for a future role in MY family unit. So.many men think that it's their presence, as The Man, that makes "a family". That they will discipline, set the rules, and be the one who calls the shots... I needed to be very sure that my partner understood that that wasnot how it was going to go. Ever.
We did move in together, after my DC knew my partner for 2 years. And it has gone well. But it was so slow op. It had to be.
I'm reading your story and I'm worried for you and you DS. 5 nights a week with someone who takes his very normal emotions as a personal insult... I'm sorry, that's not ok. This is meant to be the honeymoon period, this is as peaceful and easy as it gets... your bf is already trying to call the shots, be moody, tell you you're parenting wrong....
This isnt good for you or your boy. It's not meant to feel this way xx