YOU SAID:
I think my girlfriend is cheating on me
INTO JAPANESE
私は私のガール フレンドは私に浮気と思う
BACK INTO ENGLISH
I think I flirt with my girlfriend
INTO JAPANESE
私は私のガール フレンド浮気だと思う
BACK INTO ENGLISH
I think my girl friend cheating
INTO JAPANESE
私は私のガール フレンド浮気だと思う
BACK INTO ENGLISH
I think my girl friend cheating
That didn't even make that much sense in English.