How do I start a new life after my husband has forsaken us?

My husband left us for another woman in June 2008 and now has a child of their own who is turning 4. I tried so many times to find ways of suing them (asked advise from PAO) but told me CONCUBINAGE is a very tough case to be proven (she detailed circumstances and evidences i need to present the court). Having been so stressed that time that I was working and then working all alone for me and my 2 children, I let it pass and continued with life. My children never got assistance since he left (he has no job according to my in-laws). What can I do to finally and legally get out of our marriage to start my life fresh and give ourselves total freedom from a marriage that does not bring us its true essence anymore?

The fact that they already have a 4 y/o child, that is your best evidence that they have committed the crime. As for the support, send him a demand letter and file economic abuse case.