I used to have this problem some time ago. The thing was that I never thought it was wrong. I saw it as saving for the rainy days.
I remember vividly how people would call me names and gossip about me secretly because I never liked giving. Now, I look back and smile when I remember the names they had conjured and cooked up for me. I heard words like 'stingo' and 'arkagon' used for me. Now, it's all past.
I will tell you what I did which I think might help you.
First, I had to consider, 'where these people saying the truth or were they trying to spite me?'
You have to be honest with yourself about your attitude. I began to watch others and see how you they reacted when it came to releasing what was theirs to give. I was shocked how people didn't think much about it before giving out. I began to see how different I was.
Another thing I considered was that they could not all be lying about me. If more than three persons had same report about me, then, there ought to be a measure of truth in their words.
Also, I began evaluating if I actually needed to hold everything back. I began paying attention to words like 'Givers never lack'. That statement is very true. I can tell you that without any iota of doubt. I began to derive pleasure in giving. The truth is that when you start giving, you open up rooms for more to come.
I had to start looking at others and realizing they actually need some of the things I have more than I eventually needed them. I began to feel happy. There's true happiness and a feeling of satisfaction in seeing others pleased.
I hardly regret giving these days because it somehow always come back to me.
The liberal soul is ALWAYS made fat.