Chris142, your wife knows how much fun it is to swim and go to the water park; she wants to share that with you. You cannot change that.
Anyone can learn, but it is slow going for adults, and anxiety is tough to overcome. I learned to swim when I was in my early 30's. I had anxiety in the water and before lessons especially. Once I realized that fear and anxiety are not real -- that your brain creates it and can also control it -- I was able to force my self to just keep showing up at the YMCA for lessons. My goal was to attend. Every once in awhile I would make progress, be able to do another skill. Took a couple or three years, but I ended up as a pretty good swimmer, something I couldn't have imagined before. It is so awesome to swim after all these years! I swim all the time now and I feel incredible self-pride for having stuck it out and reaching my goal.
If you want to learn to swim, I suggest signing up, letting the instructor know your situation and just keep going to each lesson and sign up for each session. Don't expect progress right away; expect a long time commitment. If anxiety is getting in the way, go to a counselor for a session or two to learn some coping / control strategies. It is hard, tough, trying work but well, well worth it. Good luck.