@Thismorninggoingdownhill I'm probably just like your OP in this sort of situation.
I'm a fixer. Come to me with a problem, and I'll try and fix it. This works great when there's something to fix, but if there's not, then I'm screwed.
So when DP's mum had cancer and died I was crap. Not about the things I could fix, tears I can fix with hugs, DP feeling overwhelmed I can fix by making sure I'm on top of everything round the house, I can cook meals for DP's Mum and Dad, sort out funeral stuff etc etc.
But the root cause of all this is cancer, and I can't fix cancer. So DP wants to talk about it, and I can listen, but I can't add to the conversation, because I'm lost, there's no fix. Instead I'm getting cross, because something is upsetting DP and I can't help. And cross isn't helpful here, so I'm busy trying not to get cross and I'm utterly failing to think of anything useful to say in this conversation and Oh God I'm fucking up here.
A couple of years later my Mum gets cancer and dies. Again, fixable things I can do. I support, I help, I listen, I hug. I don't talk about it. My Mum talks to me about things she wishes she'd done, that she'll never get to meet my brothers children. I sit and seethe quietly. It's fine, my Mum knows what I'm like, she knows I'm listening and remembering the funeral arrangements, and which of her friends are allowed to see her towards the end and which aren't, and where the will is kept . I'll remember that, my stepdad and brother won't. But they will be able to say the words that I can't.
And then she dies. And I am on it. There is so much stuff to do and fix, and I can do it all. Funeral, bosh, selling the house, bosh, executor stuff, bosh.
And then the stuff starts to run out. But I'm fine, I haven't cried, I haven't talked about it. But Mum is dead, there's nothing left to fix there, move on.
And DP is quietly horrified. She's found out over the last few years that apparently she's with this cold emotionless robot of a man.
Until one night we're watching an episode of Buffy the Vampire Slayer.
Spoilers below for a 30 year old TV show*
Buffy's Mum dies. And the episode is widely regarded as the best depiction of the reality of what going through that experience is really like. It's horrible and real in a way that most depictions of grief in media aren't.
And I'm fine. DP wants to skip the episode, so I watch it by myself. I'm fine.
And then we watch the next episode together and I'm fine right up until:
DAWN: (harshly) Yes it is. Mom ... died, and it's like you don't even care.
BUFFY: (shocked, with tears in her eyes) Of course I care. How can you even think that?
DAWN: How can I not? You haven't even cried. You've just been running around like it's been some big chore or something. Cleaning up after Mom's mess.
Buffy slaps Dawn across the face. Dawn yelps and puts her hand to her cheek. Buffy puts her hand over her mouth in horror.
BUFFY: (tearful) Dawn ... I've been ... working. I've been busy, because I have to- DAWN: (tearful) No! You've been avoiding me.
BUFFY: I'm not! ... I have to do these things, 'cause ... (crying) 'cause when I stop, then she's really gone.
And I'm sobbing. Half an hour later I'm still going, big heaving sobs. DP is rapidly reassessing her opinion of me.
Just because your DH can't talk about it, it doesn't mean he's not feeling it.