Anyone who talks to you - especially husbands and relatives - knows that you're a writer. They're going to pop up in your books and there you go. If feelings get dented from time to time, you're not responsible. Or only a bit. So long as you don't write out of malice, obviously. I admit there's a grey area - parents, people you knew before you began to write - but you're immortalising them, after all, and that should be worth something.
The truth, the real, is fluid not static, though once written it can become static, and in this sense it can distort what really happened.
The 'I' of the first person...papers over the fact that we are no longer who we were. Each day we wake up a different person. We constantly remodel the past to accommodate the needs of the person we become in the present.The back story may well be the true story but its telling almost always involves a degree of interpretation and therefore to some extent the fictional uses of imagination.