My Fiance Is Depressed - Fall Out / Loss Of Love

My fiance is depressed.  It is my belief that he has battled depression his entire life but has been in denial of it until recently.  We have been on and off again for 3 years.  While we are together, we experience about a month of good times and then many months of struggle where he seems to get "lost."  This has, of course, triggered my own feelings of abandonment and loss.  I  have been working intensely with my therapist to overcome these feelings for myself.  While we are apart it seems to me that he begins to think more clearly and is able to return to our love.  We have done this cycle twice.  Each time we get closer, he does something to pull us apart and I react in a way that he hates and finds overwhelming. This time I am determined to use all that I have learned in therapy and have been applying it to our relationship and our relationship has been significantly better.  

We got engaged in early May and were set to be married in August.  One week after getting engaged my SO went on a business trip to the Philippines.  He looked up brothels and went to one.  When I confronted him about this he said he did not tell me because he was ashamed but that he did not do anything.  That he proposed and needed to "draw a line" and needed to be certain he can "walk away."  When he got there he realized he wasn't interested and left.  His remorse and clarity from this, as well as his connection and vulnerability with me during this time made me feel certain that it was less about me and more about him.  We got over it. ( I should mention that he was previously married and has had a history of infidelity.)

One month after that he went on another business trip.  Of course my anxiety was heightened and he reassured me that everything will be ok.  Needless to say, it wasn't.  Supposedly a man in the conference he attended almost died and had to be rushed to the hospital.  This triggered his fear of death and he began to drink heavily.  I then called his hotel room at 3am just to have a woman answer.  The next day he told me they had just gotten there and nothing happened she left right away.  He was beside himself.  He was saying things along the line of "just give me a gun", "just get away from me, I'm no good for you," "it's over, how can I ever look at you again knowing what I've done to you."

He came home and we talked about it and again his remorse and vulnerability helped me feel connected to him and my therapist helped me understand that I was not to blame.  As we worked it out he came to me, hugged me, and said "Thank you for being so good to me.  I will be good to you."  Many good things came of it, he stopped drinking and has begun to see his own therapist.

We were good for a few days then he began to withdraw.  Again, anxiety heightened.  I fought for him to open up to me but he couldn't.  He continued to tell me that it is not my fault but that he no longer feels the certainty of our relationship.  As this is the case, he has called off our wedding (to happen today) and has completely withdrawn from me.  He has told me he feels depressed and is unable to return to me.  He also told me that the more I talk about it, "it doesn't help" and "pushes" him away more.  Yet, I am a person with feelings too and I am deeply hurt by all that has gone on.  More so, the lack of connection has begun to intensify the feelings from the two previous events.  As if I am feeling them over again and cannot find a reason to work through them.  

I can assume that when I put these things out there and I show how hurt I am he has many feelings including inadequacy and pain that he has hurt me.  I can also assume that his depression, not me, is to blame for the initial withdrawal and that perhaps therapy and alcohol withdrawal have caused many feelings he has suppressed over the years to come up.  It's all rational in my head and all makes sense until it's not and my feelings take over.  I am trying to stop myself from becoming too hurt and facing a depression fallout.  

I love him with all my heart but as I sit here and write this I just wonder what will become of us.  Am I strong enough to deal with this?  Will it ever get better?  How many more times does he have to go through these depressive episodes?  How much time is enough?