How to find a former soldier I had romance with 10 yrs ago? Lives in CA but unlisted everything.?

When I was in the military I had a romantic relationship with a soldier. We were both military nurses, male-female and neither were ever married. He had 5 yrs to retirement at age 42 and I had 7 yrs to retire at 41, and both are retired now from military service. He went into medical teaching in CA and I continued nursing in PA after both were discharged. I kept in touch with him until I met a lovely guy locally, then I quit contacting him and now I regret my actions. It is now been almost another 10 yrs since my last contact, and I tried to locate him through professional services but have been unsuccessful. After all this time I realize I never should have left him and wish to find him, if possible, and let him know. Any ideas as to how to find him. His former employees, a nursing institution, have no current address or contact with him. I found out he was alive and filed taxes in CA in 2003, single status. He was originally from my area and all his relatives are deceased.

It was suggested I employ an agency that "searches for" the individual I am looking for. I already tried 3 of them, and I stated so in the original letter where I said "I tried to locate him through professional services" but thank you for your input.

Hire one of those firms that find people. The one I found below is located out of CA!