Normal to feel more mad after an apology?

Is it normal for me to get more mad atter my partner apologizes? Not long ago, my family was having a meeting because my grandmother is really sick. I saw my partner look at his phone and it just made me mad because he is always on his phone and ignoring a situation! Well, i went off to cool down and when he found me we talked for a little. After everything i said, all he said was sorry. Idk, it didnt feel like enough...he does it a lot, all he says is "im sorry" and expects the argument to just stop.

NOTE: my partner and i have been together for 4 years and he does this often. He claims he "doesn't know what else to say" no matter how many times I ask him. I just want to know if I'm over reacting and he's being honest, or if it's justifiable for me to be a little snippy still. Thank you guys for the help