One difficult aspect of a divorce is losing touch with people you care about, such as in-laws. It might be particularly difficult to lose touch with your mother-in-law, especially if you and she have a good relationship. After enough time has passed after the split, though, you may feel comfortable enough to try to reconnect with her by sending her a letter. If you do, keep your note short and simple and focus on the positive aspects of the relationship the two of you once had.
Wait for the right time. Only you will know when the timing's right to attempt to reconnect. If there were hard feelings among family members about the divorce or separation, it might take some time -- perhaps years -- before you feel comfortable reaching out to her.
Open your letter with a sincere, simple beginning. Let her know why you're trying to reconnect -- for example, you miss her, she had meant a lot to you, you would like to find out how she's doing, etc. If you have children from the marriage, let her know that her grandchildren miss her, too. Tell her that you have been thinking about her, and explain why you had not tried to contact her sooner. Make this opening section of your letter only about three or four sentences.
Remember the good times. In your letter, remind her of some of the positive contributions she made to your life, such as good advice she gave you, so she'll know that you're being genuine. Briefly mention any highlights in your children's lives. Make this portion of your letter no more than five or six sentences; you don't want to overwhelm her. Do not try to make up for lost time by cramming too much information.
Ask her to write back to you and let you know how she's doing. If you would like to get together -- and you feel that it's appropriate to ask her -- tell her that, although, do not push the issue. If she's up to it, she'll likely suggest a meeting time/location in her response. Make sure that she has your contact information, including your email address and phone numbers, and let her know that she may contact you, if she'd like to do so.