I’m sorry for your loss Jack. I think about my relationship with my father a lot lately. My uncle has terminal cancer and only has about 6 months to go. I never had much of a relationship with him so when I found out that he was dying, I immediately began to regret the fact that we didn’t get along, mostly due to me. So I’ve used this experience to build a better, more intimate and tangible relationship with my father. You never know when someone might go. It sounds like you and your father had a good relationship, despite all this unfortunate business with his wife and kids.
I’m hardly one to offer words of wisdom to anyone on this site, but I think that one of the worst things about the death of a loved one is the possibility that you haven’t vocalized your love for this person and really told them how much they mean to you before it is too late. But it sounds to me Jack like you have had that opportunity, so perhaps you can look to that as a source of comfort in these times, especially when taking into consideration all that bullshit with his wife. It’s not important what they think. What matters is that your dad died knowing how much you loved him and what he meant to you.