So sorry you are here.
I've got to back up what Jrazz said, just because you don't have proof doesn't mean he's not busted. Keep digging.
Have you searched for the number on FB? If that's a dead-end pay for a service to do a reverse cell look-up if you must, they really don't cost much compared to your peace of mind.
Also, your profile doesn't say if you're married or not but a spouse going MIA for days is abandonment and you should contact a lawyer ASAP, if that's the case.
I know this is a brutal time you're living in right now. You will get through this. Keep your focus on yourself and your DD. You don't have to make any major decisions at the moment but you will have to keep your wits about you and stay sharp in the coming days because your partner is pulling some major shit!
Sending strength and hugs (((Foolme1))).