My dog's demeanour changed when I was pregnant so maybe he has started protecting you?
I was going to say that too. My beagle has always favoured DH, until I was about halfway through my pregnancy. Then she was all mine! Followed me everywhere, sat at my feet, everything. He couldn't get a look in. After DD was born, beagle is back in love with DH! They certainly can change when you're pregnant. Could be that your lab is doing a super job at protecting you.