Frenchie, (I was inspired to reply. This may help FC, but it may also help those who are in the same kind of situation as FC)
learn to forgive yourself and the ex.
You need to release any and all contempt and hatred.
Resentment is toxic.
Remember the famous Mandela quote (paraphrased):
"To hold resentment is akin to drinking poison and hoping the other guy dies."
Your failure in reltionships with women may be caused by the problems with perception and vision of yourself and especially , women.
Add in the factor in how you viewed your Mother as a Woman, and now you have a conflict of perceptions with women. Perhaps you idealize your Mother, now that she has passed away you have no positive image of women, throw in the behavior of the ex, and you've got serious issues in perceptions about women, and you interactions with women.
You may now view all women as your Ex, and feel that all women will automatically behave in that way.
You also may see yourself as a failure, and the impression is so strong, that you only keep reliving the same kind of negative scenario.
Not wanting it to happen again,perhaps you shut down, and refrain from engaging in relationshiops with women where you'll feel vulnerable again.
Let go of the resentment.
Let go of feeling guilty for not "doing better."
Let go of believing that you have to be the same person forever, and that you are sentenced to repeat past mistakes and experiences over and over again.
Learn to love and appreciate women again.
Appreciate who your mom is, and what she did for you. emember those outstanding qualities of hers, and wht you admired about her. Realize that women can be good people. Your dear mother was a "good woman."
Your ex was simply not one of them.
All women are not your ex.
There are good women out there. But the more negative YOU are, the less chance you will have in finding them.Raise your vibration. Think with your Higher Self, and learn to trust in your spiritual beliefs, and the gut instinct that knows your desires.
To follow a spiritual path is to follow a path of happiness and freedom. And especially, continued growth , and appreciaton for all things.
You don't have to live a life you don't desire.
You are not your Depression or your sadness.
You are not directly responsible for your mother's life. Don't live as if it was your "fault". Remember, you're a grown man now.
You are indirectly responsible for the situation with your ex though.
How so?
Because you invited that woman into your life. Take responsibility for that. Be a man. accept that it happened. But it is in the past. You gain nothing, absolutely nothing from reliving it. And that might be what you've been doing.
Reliving those past mistakes, ruminating over them, obsessing over them can keep you in the pain and the darkness.
Letting go of all that takes you to happiness and fulfillment.
Don't give the ex that control over your happiness and wellbeing.
Let go of identifying with the pain.
Continue to learn , explore, and grow.
Discover yourSELF.
P.S. I think depression sets in because of frustration in not living the life you really want. Frustration is desire unfulfilled.If people really knew that the secret to life is simply do what makes you happy, there would be more action in that direction.
Remember,"Follow your bliss."