well, clearly there are a couple of things that standout.
Your dad's biz is just that: his biz. Who he lives with, who he dates is: his biz. Who you play tonkas with at your house, who you play bingo with at your house, if your house is painted pink with yellow polka dots...
if the cookie monster leaves cookies on your lawn: that's your business.
However, YOUR relationship between your father and you is just that: YOUR business. Tell him how you feel. He might nod his head twenty times. He might not do anything. The result will pretty much be the same: you got it off your chest.
Maybe as an adult you can tell him how you felt about the divorce between your parents. Even though it was THEIR relationship-it clearly WAS your business. You might tell your mom how you feel.
And that's what it comes down to: feelings. Talk to your husband.
Tell him how you feel. THEN: Get on with your life. It appears your dad has. Not so much with your mom, I think.
Accept the fact they are divorced, have been, have separate lives.
As YOU do with your husband and child. YOUR LIFE, not theirs.
Many of us have extended family; and for the most part-are living their lives without a thought about what we think. I'd say that's pretty normal. I moved outta the house over twenty years ago-and you know something? My bro has his own life; he's married, got a house, got a job. My mom divorced when I was 10-the last time I saw my old man I was 12-my mom re-married-they had a kid-yada, yada, yada. I've been living my adult life for some time now: my decisions-my business. A year ago or so I talked to a close friend. He told me I had some things I was holding onto and he SUGGESTED I put them in my God box. I listened, then I took action. Do I feel better? Heck, YES! The time will come when you have to decide to let go of the ideas and feelings that happened a long time ago. Ultimately, no one can makes those decisions for you. This is the journey of life. There is no book-but there are countless numbers of folks who can clearly demonstrate how they've dealt with a situation like yours. In all likelihood, perhaps you should discuss this with a friend, one on one, and then go from there. I think you'll find some closure, and acceptance.
Well, that's my two cents.
Good luck.