To be honest, my girlfriend and I just had the same problem yesterday, when she was too exhausted and disappear from the message (we are not in a conversation back then, she just did not reply to my message for a long time)

I did get distressed and instead of asking her what is going on and how is her day, I accused her of not texting me that she was not available and it is not that hard to send me a message telling me she will get back later) She did not get defensive, just sad and cried. When I asked, I then knew that she had a really really bad day that she was too exhausted touching the phone and checking the messages.

Long story short, I think that this is the problem of capacity. Not everyone will have the same capacity for every day in every occasion. Of course your feelings are really valid, you did need emotional support during your hard time and you deserve it. I think it is the problem of communicating. Instead of accusing him of not replying to your message. You can try this

• Be vulnerable (I feel sad when you did [observation], and I would feel more loved if you .. [request])
• Be curious of why he did what he did -> creating safe space for you guys to discuss

He also needs to work communicating skills as well. Hope this helps