Depression. That i die. please advise.

I feel very sad and dont want to do anything. I dont like anything. This has been going on for 10-15 years. I dont feel like working and at present unemployed. I had gone thru divorce since 2002 till 2007. Got remarried in 2011 and hv not had good relations with wife and her 2 children. Only recently have my children from earlier marriage have started interacting with me. Earlier they did not interact and that caused lot of pain and i just did not wanted to live. Thought marriage would help but it has caused more distress because of feeling of inadequacy and continuos stressful interaction and expectations from wife and marriage. Presently they stay seperately and i support them financially and wife is working also. Have become diabetic and for last few years having problem with erectile dysfunction. I dont feel like interacting with people and also dont want to go out of the house unless required. I dont hv suicidal tendenices but wish that i die. Please advise.