I don't have any answer for that - I don't have kids, but your post just struck me as a daughter of divorce with a father who remarried, had step-kids and he drank.
By the time I was 11, I was done with his selfishness and dishonesty and did everything in my power to not see him. He lived quite a ways away and never made much effort anyway - from what I could tell.
He died on my 16th birthday. It took until I was 40 to "get over" it - but not because I hadn't spent a lot of time with him, because he was such a liar and seemed not to care about me at all. It was the anger I had to get over, not sadness. So, I certainly see both sides. The side I never thought about until much later was how my mother felt about all of it.
I send you love. That's all I've got.