It’s often because we are caring, loving individuals who trust and want the best for others. Sadly it makes us easy targets because all we want is to make the other person happy at our own cost
I often wonder this too but the only reason I can think of is because they CAN. And how awful?! But please try not to let this thought take over as it is sad to think that some people think abuse is acceptable.
Think of the positives, you are kind and caring, willing to give people chances. Only the wrong people will take advantage of this but think of all the people who will give back to you x