Life has certainly dealt you a hard hand in recent years.  I'm so sorry.

As Joy mentioned, no one knows what causes arthritis.  However, stress and depression do make it harder to live with arthritis.  It is natural for you to have quite a bit of both stress and depression and I think seeing a therapist or counsellor could help you deal with the hardship you had to face in the last few years, as well as develop coping mechanisms for living with a chronic illness.  Your wife may also benefit from this - you'll need each other in the time to come and talking to someone about what happened can make you stronger.

The best advice I can give you is to find a way to leave the past in the past.  Carrying the sadness and bitterness around will make your present and your future a hard and dark place.  I know that sounds much easier said than done and as with all losses, this one needs to be grieved.  But when you have grieved, find a way to move on, find meaning in your life.  Find joy.  A lot of choices were taking away from you, but you still have some choice and control left.  You can choose how to live today.  You can choose to try and find peace.

You can do a number of things to help you let go of what has happened to you and to learn how to manage stress and pain.  Talk to your doctor about your depression - he or she can assess whether you might need antidepressants to help you over the hump, as well as refer you to a good counsellor.  You can also try meditation or yoga, which can help when dealing with stress and pain.  Massage and acupuncture may also be helpful.

I wish you and your family all the best.  Please write again if you have more questions.

Stress doesn't directly cause rheumatoid arthrtitis, but if you had it before and didn't know, then the stress could have definitely brought out the symptoms.  I am 28 and have had RA for 14 years and stress is almost as big of an enemy to me as RA is.  You will find that the more stress you carry in your life, the more pain you will be in.  Keep a journal to find our what your stress triggers are.  I know it sounds very cheesy, but you will find that there are things that trigger stress in your life, that you never knew about. 
That being said, I know if it virtually impossible to get rid of your stress as you have many, many things to be stressed out about right now.  Simple things like taking time for you and your wife can really help with the stress.  Now on to the bitterness.  There are many studies on how carrying anger or in your case bitterness can cause health problems.  In RA, that really holds true.  Bitterness causes stress, stress causes flares, flares cause pain.  I know you have been through a lot of things that have been devastating on you and your family.  But I also know that on to those things causes health problems.  It is never easy with RA and nobody has all the answers.  You have to learn what works for you.  When you are flaring it not only affects you, it affects your wife which must be devastating for her too.  Take time to relax and reduce your stress.  Try it for a month and see if you are feeling better.  Good luck and best wishes!