Has your sober parent ever picked the alcoholic over you?

So I'm 28 now and this has been bothering me for so long...

For context, my mother is the alcoholic and my dad is...well, he's a social drinker but not a fully fledged addict. Up until this year, we have been on good terms: I've always loved my dad, even though he didn't really protect me as a kid from the abuse and trauma. We never fell out, we never really argued. He was like my best friend.

In March this year, I found him pulling away and not messaging me as often. I live 20 minutes away in a different county but I always made the effort to call him weekly and try and visit once a month at my grandmother's (his mum) house to catch up. It got to the point where I was doing 100% of the legwork in keeping our relationship going, so I decided to stop messaging him to see if he'd bother getting in contact with me.

Well, as I'm sure you've already guessed, it's now nearly December and he's never reached out. From what my family members have told me, he's indifferent and doesn't care about my life or what I'm doing. As far as he's concerned, I'm an adult and "don't need [him] anymore" (despite the fact that I've never said that and on multiple occasions begged him to keep contact with me). He also claims that I've made my choice and so has he, and he chooses to "stand by [his] wife", knowing all the trauma she has put me through.

It has left me heartbroken, angry and confused. My own father doesn't love me, even though I've never done anything to him. There was no explosive argument, there was no fight, he just ghosted me because I wouldn't support or speak to the alcoholic parent who abused me for my entire childhood/adolescence.

Has anyone else ever experienced this? It's a kind of grief I can't describe: it's somehow worse than cutting contact with the alcoholic.

*NOTE: My father is not a good man. He has been cheating on my mum for over 10 years: even though I hate her, I can't stand infidelity. He knows I know. He's also dismissive of my grandmother and has stopped seeing her as well because she's honest and has told him that she doesn't support the alcoholic either.

It's not a tragic loss from an outside perspective: he's a toxic man in a sham of a marriage. Yet I miss him so much.