My husband left me 2weeks ago and has a new woman?

2 weks ago my husband told me he didnt love me anymore. we have 4 children (2 are mine from a previous relationship) our eldest is 10 yrs and youngest 10 mths. i still love him dearly but he has moved in with another woman. she is 45 i am 27 and my husband is 22. we have been married for 20mths and had problems 9 mths into our marriage (again he said he didnt love me anymore. iam so depressed and feel mangled inside. i really want him back and cant see any future for me. i love my children and would never leave them without a mother but how will i get through this. i saw him today and asked him 2 choose between her and his family . he said the choice was between her and me and he chose her. he is my life and as much as i have tried i cant fall out of love with him. i have said some very hurtfull things that i regret and dont know where to go from here. how do i get him back?