Personally, I wouldn't use the Journey Map itself to validate with customers. I'd use research methods to understand your customers and use that to validate your Journey Map.
Questions like: "Walk me through the last time you did X. How did you go about it? What initiated it? What was your intended goal? What steps did you go through? What worked well for you? What were problems for you?" Using these types of exploratory research questions, you get the data you need to validate your Journey Map as far as stages, needs, problems.
Also, to that I would add observation. Observe what your customers actually do.
Ultimately, a Customer Journey Map should be an artifact that represents what you know about your customers, which you get by research.
Nothing wrong or bad about starting with a provisional Map as you did. I'm wary about using it or your preconceived map to validate as it may bias or lead customers. Open-ended interview questions will discover their needs which you can then compare to your Map.