Need to vent..

I have been with my boyfriend 8 years now we have 2 kids but through out these years we have been through rough times like any other relationship has. The problem with him is that he is controlling and always wants his way he has been unfaithful in the past and i have tried to put that in the past but ever since i found out its hard for me to give all of my love to him i feel resentment towards him. Everytime we argue he shuts me down and we never solve the problem so that feeling of anger that i have i need to put it aside and have it in me but for the sake of us not being mad at each other i suck it up. I have tried everything for us to be happy but nothing seems to work he will never change and the more time passes by i am slowly giving up it is just so hard to throw 8yrs away but idk what to do anymore. We were ttc but now that i see no change in him i honestly don't want to have another child with him.. Anyone who went or is going thru something similar what advice can you give me. TIA