My son never liked the water. I am not sure he had a bad experience but I spent thousands of dollars on swimming lessons and he rarely got in the water.
My other 2 were right in the water and continue to swim. He is now a teenager and is taking swimming lessons. ( doing very well) We just went on vacation and I was surprised to see him in the waves.
I would suggest you let your son go at his own pace. Let him first play with water.( pouring water from cup to cup)I would not "put" him or throw him in the water. He will go when he is ready.( or when he is hot!)
On another note,with a background in sales and marketing, you should start your own business. I started selling jewelry about 1 year ago and am doing very well on my own schedule.
There are numerous home sales businesses that your background may help you with.
Good luck...