Yes you should speak to her about this. You could sit your mother-in-law and husband down and talk this issue out. What could draw jealousy and insecurity in your mother-in-law is that she is probably seeking to spend some time with her son or you both together, but you and especially your husband are unable to make time for her because of a busy schedule; nevertheless you and your husband make it a point to go out on weekends to spend some quality time together. The mother-in-law is worried that her son is getting distant from her and that you have taken up her place in his life so that she feels left out and unimportant. Address both her insecurities and your issue when you sit together. Also make it a point to spare some time for her; talk to your husband about making time for her as well; a few hours in a week would do. All the best! Let us know if it helps.