Emotional attachment to pregnancy.

I am 10 weeks and my SO and I were able to see our little and hear the heartbeat a few weeks ago. My poor SO is having a hard time with this pregnancy. He has dreamt of being a dad for a long time and I guess his expectations of pregnancy were so high. He wanted to be the guy who tended to my every pregnant need and share the intimate moments with me. My pregnancy has been really easy so far so I have just been independent and being myself. He is depressed. I think he feels uninvolved and like a third party. I thought seeing the ultrasound would have made it more real for him but he still doesn't connect. I've heard this is common for dads to feel unattached, some even up until the baby is placed in their arms. I feel bad for him because he has looked forward to this for so long and he feels guilty for being unattached and distant. Anyone else going through this ? Any tips to make him feel better?