I agree with all the advice from other posters, you need to tell him & prepare yourself that he may well not want to be that involved other than financial support & he has probably moved on & met someone else.
I'm guessing that the baby wasn't planend so it will be a HUGE shock to him & he may well not be that overjoyed, especailly if has met someone else.
You really need your friends & family around you, especially for the 1st few weeks and beyond and do get yourself involved in groups/classes etc.
Good luck & I cannot describe the joy that you will feel when you first hold your baby & the love that you will feel, no matter who awful things seem now. It is the best feeling in the whole world & the best thing I have ever done
Take care & keep us posted
x