My partner became a widow not unexpectedly 4yrs ago. Since being together his true self has evolved and blossomed, his past relationship was dominated by wife and two children.

he said he stayed through her illness out of marital vows and I commend him for that. But it has had a lasting effect in that the children immediately tried to take their mothers place by dictators of his adult life.

namely meeting me dating me and now living together they have on three occasions split us up , his reason for taking there side was he felt sorry for them and as his wife spoilt them he felt he now had to be mum and dad to two kids in there 20's.

One child turned his back on our relationship the other has stayed around and makes a point of only calling when she is depressed which goes to money which goes to him making promises he can't keep.

I am totally ignored unless it is for him to discuss the issues she has with me then go back to her a knight in shining armour. 
I'm not looking for credit, I simply feel I'm a source of help but shown no respect or gratitude I doubt she even knows it's me behind the scenes making suggestions, I have four grown children who all hold there own and do not interfere with my life. Does anyone else feel like this or am I being selfish ?

I don't care what he does financially it's his money let her spend it but live frugally and keep a good home and pay my way.