There are many different possible circumstances to each choice. The best choices are always made when you are being honest to yourself and to others. If you happen to make any other choice, it will surely not flow consistently and in a normal pattern, therefore the results will not be consistent and normal. The determination of these factors is something only you can control at the given moment, and each moment varies in complexity.
We have all made disastrous decisions in our lifetimes and I am sure that there may be some regrets that are attached to those decisions.
You shall not let these past decisions affect you anymore. The energy that is attached to your regrets will encompass any of your future choices and will assure the same type of results. Letting go of such regrets will allow you to move forward by giving yourself a level of self-forgiveness.
The act of self-forgiveness lets you grow forward and even if you affected others with this decisions that you have made, your individual growth and forgiveness will be a positive energy that everyone will notice while in your company.
One will say, "They have changed", and the circumstances of your new, positive, self-appreciating self will only get better in time.