Doctor works as an university professor. MJ volunteers at an animal shelter, and if I remember correctly, he later decides to study again. MJ also bought a house for them to live in. They are cute! Doctor brings flowers and desserts for MJ all the time. And they never throw away the flowers, they decorate them all over the house!
In the beginning, doctor used to have panic attacks and hallucinations of 'Father' but it got better later on. In last chapter(s), they exchanged rings, but I don't remember if they were proposal rings or promise rings.
About Crack, I don't remember a much! Ice met Doctor and told him that Crack is back and is planning to take down MJ. He was petty that MJ was free from it all. He planted a bomb somewhere and either wanted to put blame on MJ and get him back in jail...or he wanted the doctor and MJ to die in the bombing.
Doctor convinced Ice to play the double agent and that ultimately lead to Crack's plans failing. Crack went into hiding with no possibility of return. I don't remember how exactly the plan failed but mainly Ice betrayed Crack.
Ice was also free from all the shady business after this.

There are more side stories in the novel focused on their life after MJ's release. If anyone's interested or have any questions, I can try to answer them!
There is an arc where Crack returns and tries to ruin their life. He fails. (I don't remember this arc in detail, but I will try)
There is also some chapters focused on ice and grizzly (?). They end up together. (Sorry, I skipped these chapters! They do end up owning a restaurant though)
Note: I read these side stories on booktoki (rip), so I don't have a link anymore.