Need advice

Four weeks preg tomo and my bf that I have our 17 month old son with says we are not ready but when we were intimate he said he did it on purpose now that we are expecting he doesn’t think it’s a good idea to keep the child my heart is torn I want this baby but I have no support and I am feeling extremly depressed and low about everything going on of course I am to blame as well but why would u say u did it on pirpose now that I am preg u feel I should get an abortion I feel if I got it mentally I would be so destroyed any one ever went threw this please leave some advice please no bashing