Ask a Psychiatrist and Get Answers to Mental Health Questions ASAP
Sorry to hear of the situation. Just to clarify, is your wife doubtful of the possibility that you can improve your self esteem (and as a result improve your marriage)?
Psychologists often work with people to improve low self esteem and I would suggest you show her this self help program here - http://www.cci.health.wa.gov.au/resources/infopax.cfm?Info_ID=47 .
I use this program with clients regularly and it contains detailed information on what exactly low self-esteem is, how it develops, how it is maintained and how it can be improved/changed. The information in the early modules is quiet detailed and if you were to take her through it she would see the theory/mechanics behind how we are able to make changes to low self-esteem. You could also refer her to the literally hundreds of treatment books written on the topic, all of which clearly stated that low self-esteem can be dramatically improved.
I hope this is of some help. Let me know if you have further questions or if you would like me to clarify anything I have posted.