I understand Michael “distancing himself from his family [crime] business” but why from his family?

It was strange indeed Michael in his Marines uniform, with his 'American' girlfriend in tow, turns up late for his sister's wedding, then goes and sits away from everybody and everything

Michael didn't go to see his father, mother and siblings, doesn't congratulate Carlo and Connie, the bridal couple

“He certainly knew that, after he killed Sol and Mac, he would never be a "civilian" again” though Vito's speech at the peace meeting 'cleared' Michael of all these false charges!

I believe Michael's involvement and killing of McCluskey and Sollozzo, was solely and all about protecting Vito, at that stage

In fact with the war, everyone would be expected to take extra precautions If not for Carlo...
The Corleones couldn't locate Sollozzo even with a hundred buttonmen on the street, twenty four hours a day! looking for Sollozzo