We had a similar situation arise when DP's colleague returned to work after her maternity leave - even though we weren't ttc (and so didn't have those other, seperate but mixed-up issues) I found it a little hard to deal with.
As beetroot has said - he sounds like a great guy, so many blokes (even those with kids) don't realiose how dreadful those first few weeks back in the workplace can be. I was glad DP was helping this girl out, but wanted him to show the same consideration to me... In the end everything was ok, and I managed to let it go.
I guess at the end of the day when we are at work its easier to be thoughtful, giving, spend more quality time on MN etc than when we have squalling DD and Ds's competing for our attention, or when we are exausted having put them to bed...