Recently my ex-wife and I have been seeing each other and talking and we have been divorce for about 8 years,?

we did get back together about a year after the divorce but we were not re-married. She started drink again after receiving help for her alcoholism and I left her after being together for 5 years. Her dad paid for about a couple of months the bills and rent on our house. Her dad reminded her of that today. I believe I left for a good reason. My ex and I have talked and agreed about getting back together and taking it slow and easy. So how should I talk to her dad because I think at the time my ex and I were pretty immature and now since we are older we both agree that we have made mistakes and are mature. Hope this all makes sense and any replies will be helpful. Thank you.