DS was totally like that from when I started showing - all the way through - up until about the last month of my pregnancy.

Then all of a sudden - he turned into a daddy's boy... I think what helped is that DH would get up to resettle him of a night time because it was too hard for me to lean over the cot to resettle. So I think DS got used to that extra contact, at a time where he needed more comfort IYKWIM?

Now that things have settled down - he's back to being a mummy's boy

I have no suggestions - but just letting you know that there is hope