Yes, it's hard being a single parent, whatever the cause might have been. And I'm sure you're right; it must be even more difficult being a single father. One reason I wanted to reprint your letter is because I hope it will make us more sensitive to the difficulties single parents face.
The greatest encouragement I can give you is to assure you that God knows all about your situation, and He loves you and wants to help you. Some Bible scholars have even suggested that Mary, the mother of Jesus, might have become a single parent at some stage, since Joseph is not mentioned later in the Gospels. Although this isn't certain, you can be sure that God has a special place in His heart for parents who must face life alone.
I often think of the heartache and sorrow that engulfed ancient Judah when Jerusalem was destroyed and countless parents lost their spouses. Jeremiah lamented, "We have become orphans and fatherless, our mothers like widows" (Lamentations 5:3). Yet he also could say, "Because of the Lord's great love we are not consumed, for his compassions never fail" (Lamentations 3:22).
May you turn to God for the strength and wisdom you need every day. If you have never done so, ask Christ to come into your heart, and begin building your life on Him. Then seek practical help; many churches today have special programs for single parents, both to encourage them and provide practical help for the issues they face.