You want to know how to get a Cancer man to forgive you. It's happened. You've done something that has caused your guy to feel emotional pain and to be upset with you. You already know by now that Cancer men retreat back into themselves when they've been wronged. They pull their emotions close and they are apt to hold a grudge. Depending on what you did wrong, it can take some time to get him to understand why you did it and then to forgive you. It's possible though if you understand the steps you should be taking.
Learning how to get a Cancer man to forgive you begins with understanding that these men can not tolerate confrontation. They typically will not even engage in it. If you two argued and now you want to belabor the point so you can get him to understand your side, do not do it. He'll shut right down and want distance. It's not uncommon for a man born under this sign to actually disappear for a time after something has hurt him. It's his way of regrouping and getting a handle on what he's feeling so he can express it clearly when he does talk to you.
You're also going to notice that your apology may appear to fall on deaf ears. If you try and say you're sorry too soon, he's going to discount it and think you're just saying it to be under the rug. Wait a few days before you tell him you're sorry. If you can not reach him by phone to apologize, then craft an email explaining your regrets and send it off. Do not get too mushy or emotional in your email. It's not going to have an impact on him if he's still upset with you. He may actually start to see your emotional outbursts as childish and a sign of immaturity.
Once he does start talking to you again, be direct and confident. Let him know that you are sorry and that you'll ensure whatever you did not happen again. Then set out to prove that point to him. Show him that you've learned from your mistake and that you're mature enough to recognize it.
It's important to note that of all the Zodiac signs, Cancers seem to hold a grudge the longest. They truly never forget if they do feel they've been wronged, but they will forgive. You need to be prepared to hear him bring up the issue from time-to-time as a way of reminding you that he remembers. Just handle yourself well during those times and he'll do it less and less.