My fiance left me and his two year old daughter for his ex g/f?

My fiance left me and his two year old daughter for his ex g/f. We have been together for seven years and lived together for 3 and have a beautiful two year old. We had been so happy up until June of this year thats when he started going out all night and coming home at 5 am. See him and his ex g/f had a kid together before we got together but she had told him the baby died at birth now 7 years later she came back to him telling him that the kid was indeed alive and that she had put him up for adoption. I had just recently found out that she is divorcing her recent husband and then poof all of a sudden my fiance decides to up and leave me and his daughter.He moved back in with his mom, He left us with nothing he hasnt paid anything for his daughter he spends his free time with that tramp and get this when he came back to get the rest of his stuff out of the apt i wasnt there he even took food and all of the bottled water. Now his stupid ex is sending me text messages saying that he left me for her cause he could never forget her and saying jealousy hurts doesnt it? Im so hurt and infuriated right now I dont know what to do! Does anyone have any advice? My daughter is constantly asking me where's daddy and its breaking my heart. what do i do?