Alot of ^^^^^ is pursuit. At this stage, it doesn't matter what your true intentions are, they will be perceived as pressure.
You wrote that you feel like you expressed resentment around being a "single" parent due to H working to much... so keeping your mouth shut and keeping your cool was the right call.
You won't be able to talk your way out of this or talking your way into proving that you are going to change. Just change. Let your actions speak for you....
... and give it time.
Listen and Validating to his work stress is a good step. Validate that he is making an effort to see Son.. but in a very subtle way.
So what does that look like for you?
M(f): 40 D'ed: 8/12
Show empathy when there's pain. Show grace when warranted. Kindness in the midst of anger. Faith in the face of fear.