End a relationship of 27yrs

I just came back from working overseas and discovered my husband (62)has a child(5) with a 33yr old women.He first denied,then later agreed he pays a R1000 mantainance.Obviously my trust is gone.He has always been a cheater.He does not smoke or drink,no friends and always at home.He is a Senior at work,and has ample time to do mischief ,and come back home potraying himself as an   innocent husband.I have cried my eyes out,I feel I must get out of this marriage that brought me such pain.He will soon get his pension(+R3.5m),who knows what the OW is planning.He never showed any remorse,only said sorry.We haD an argument the other day,he said he is not gonna bow down on his knees for me because I am not God.Now he plays a loving husband.....asking for sex......I am not prepared to be intimate with him......he is just dirty ,in my eyes!I think I should get my 50% share and get out!