Calm down, Make no ASSumptions. There may be an explanation - or not. Why not just call him on his new number and ask him when he got his new phone?
As for the bigger picture - you're so nervous about giving him a chance, that you'd rather push him away now than risk being hurt. Why not make an agreement with yourself that you'll give this a specific amount of time - say 6 months - and see what he's managed to do in that time. If he's straightened out - great. If not - you can dump him in 6 months. Then at least you can tell you daughters you did your best.
