Pick a good time and be honest with him. Tell him how much it will help as a couple. I will even send you a pic of my 9 inches to show and get a discussion going.
I have 9inches and I am new to the lifestyle also. I am also very gentle because not many women have been able to handle mine at first. My ex wife always kidded me that I have been a porn actor before lol. Message me if she's interested.