Dont let him be. Make sure your conditioning allows you to throw more punches harder and faster down the middle.
That advice is only bad if you cant handle it. Heart is invaluable. Couple that with conditioning and you are unbeatable.
Plus it makes for a better fight to watch.
No offense, but that is simply not true. Mayweather and Hopkins eat guys like that for lunch. If it were "unbeatable" everyone would fight like that. It works fine until you run into a good/better forward aggressor and find that you are so lacking in footwork and the ability to fight "sideways" that your only option is to get your "heart" tested to the point you simply fall down.
Being able to step in and get some is great, and someone who is a good forward aggressor can throw anyone off. If you simply have yet to train or spar with anyone who is better coming forward than you are I could see the limited view. Once you have someone you simply cant back up or beat head to head you'll learn the value of lateral movement, aggressive defense and stepping off. Till then good luck with the world title and that particular "unbeatable" style.