Sadly, your case is very common- fathers refusing to take responsibility for the children they fathered!
You did not mention the age of your son’s father though, I guess he’ll be about the same age as you. If he is old enough to father a child then he should be old enough to look after the child!
However, the problem here is that he is not contributing to the upkeep of your son. Have you tried talking to him about it?
Remind him that as an adult he should be able to make decisions about a child he contributed to bringing into this world without the interference of his parents!
The question as to whether you should give your son away to others to look after has already been answered by your own admission that you “can’t let go” of the boy and you are not tired of looking after him.
As for whether the boy will go back to his father some day, why worry about what has not happened?
My advice is: focus on raising your child and being the best mother you can be. What do your own family say about it all? They should be able to help you out financially and also give you emotional support.
Finally, pray and ask for God’s help and direction and He will send helpers your way.
Admittedly, it is difficult being a single mother but the joy of motherhood, of seeing that child grow into a responsible young man is incomparable to any pain you may feel now.
What’s done is done so get on with it! Tough? Oh yes- but you CAN do it!
Whatever you do, please DO NOT, I repeat, do not say bad or unsavory things about his father in his presence!
Let him have the memory of a good father who is not physically present in his life now (I didn’t say you should lie and praise him!).
Whenever he becomes curious and asks about his father (and he will!), try and be honest but diplomatic and remember young kids are usually more intelligent than we give them credit for!
Keep me posted and good luck!