Sexual problem. Able to talk to anyone!

Hi, I had got involved in some bad habit of masturbation.For a long time I did it n now as I am not sure if I can satisfy my life partner with whom I am getting married next month n even I am not able to talk to anyone regarding this as there are lots of misunderstanding in the society.Currently I get tension in my penis for just a fraction of some time and then it is gone.I am not very sure that have I became incompetent n can any treatment help me. I work for BPO in Bangalore n I would prefer someone from Bangalore to assist me in the treatment so that I can have face to face conversation with the specialist. I am a physically challenged person who has undergone a below knee ampute surgery just 2 years ago n I have a feeling that after the surgery this problem got worse n current situation is the one that I have mentioned above. Request you to assist me in this situation..