he said i cheated 9 years ago

so this stems from the color of my 2 boys skin tone who I call night and day I've cropped out our names father refused to do a DNA test so I did a sibling test this is bothering me because my son who is in question is 9 yrs old and this the only dad he knows I never cheated on this man smh he is half black and white I don't know what else to do especially since he won't give me a DNA test it's just been a mess all these years any advice?? I will not respond but will be reading for inputs or advice this is depressing I just want to be happy and move forward