There are many reasons that why your ex texted you first but now ignores your response.
Not only is it completely possible to get your ex back by ignoring them, it's actually an amazing technique to use in certain situations.
Accept what happened, learn from it and allow yourself to move on.
From the very beginning, he needed a bit more time to relax and get comfortable around you.
If I am not in the mood to go out and see people one day then I will not do it.
Give your ex respect, and in return, they will give you care.
However, if you are simply trying to be friends, part of being a friend is giving him the things he needs.
He is 45, never married, no kids.