Hi beky,
so sorry for your loss.
Having newborn while beautiful and miraculous can be stressful especially when you've had no sleep. Think very carefully before TTC. I know the pain and emptiness of losing a baby and you sometimes feel incomplete or that something is missing but a new baby wont change those feelings. Your partner seems open to counselling and is willing to get help, that's a really good sign. When you're relationship is back on track you will know the time is right. keep communicating with each other. Keeping feelings bottled up will only result in a big blow up and argument.
Good Luck to you both