You should cater to her "INSECURITY". She is used to a particular type of relationship with you , The obvious outcome of marriage is shared time and attention, which she may not be able to cope with especially if she is SINGLE. You should try putting her insecurities to rest by regular assurances, direct & indirect and attention. You should also try suggesting her to to adjust with the altered circumstances preferably with a help of a psychologist/counselor. And for your peace of mind, do not get deeply involved(MENTALLY) in the domestic issues, You have to strike a balance, neither getting too involved and reasoning everything and anything, nor too callous..PLAY IT LIGHT! Cheers

Hello, its heartening to see your concern for your ageing mother. Since you haven't mentioned the duration of her symptoms, its difficult to comment upon the diagnosis. Howsoever, you should know that your marriage may have spiked fears and insecurities of being left alone, uncared for or ignored, which might have led to increased irritability. This can be improved by giving her time and attention, involving her in conversation and decision making. Encourage her to participate in outdoor activities like going for a walk, going to the temple, meeting ladies of her own age, sewing, reading etc. If needs be, take her to a psychotherapist for regular counseling sessions. Good luck.