Fiancé has no interest in pregnancy!

My fiancé and I had tried for three years and we finally had our wish come true. I am now 18 weeks and just starting to get a little bump.... we found out it's a boy at 16wks and he's been to all ultrasounds. He has wanted a child for so long, especially a son. 
He has ZERO interest in the pregnancy and it's hurtful. Today was the first I noticed the bump while laying flat- I asked him to feel his baby boy and he wouldn't. Later in the day he mentioned that it was weird and grosses him out. This hurts my feelings and makes me feel even more unattractive. I  am now super emotional and upset, lovely. 
I am told "he will eventually come around, hopefully when you show more and the baby kicks".
Has anyone else experienced this? He's a great guy and would never intentionally hurt my feelings. Perhaps I am over reacting. Advice please!