Sims 3 - Missing baby?

So my married sim is a total player, and he had a baby with the neighbour. The baby was born, he visited it for the first day. Then a few days later, the baby is gone from the house. I can't find it, and the lady is already married to the other neighbour and has about 5 kids, 2 of which have died. So the baby is missing, I can't find him anywhere and his icon on my family tree is still a baby when it should be a toddler or even child since of custom aging. I tried /resetsim.... but it didn't work. Any suggestions? I think he is a toddler living somewhere since he has 3 traits.