There's no word for a parent who has lost a child because it's the loss language never expected to need. You're grieving a person and an entire future.
Nothing about the usual timeline applies. Many bereaved parents describe grief that reorganises rather than fades.
Partners often grieve at different speeds and in different styles, which can feel like abandonment on both sides. It usually isn't.
Say their name. Mark their birthday. Their existence isn't a subject to be protected from — they were here.