going totally against the grain here but YANBU for not wanting someone like that in your childs life!!
i was in a similar situ and left partner at 3mth pregnant didnt tell him i had ds until 2weeks old - should have gone with instinct and left it alone but gave into the whole 'he has a right to see his dad' etc.... anyway long story short he was in and out of my ds life for 1st 5 yrs always promising the world to him while giving him nothing, always letting him down and me picking up the pieces.
i decided after a particular weekend (i went away left ds with him - he had gf stay in my bed, smoked in house (i dont) drank all the booze and let ds cross 2 roads to go shop on his own) that ebough was enough.
moved out of the area but we had mutual friends and i always said dont give address (turn up pissed one day) but if he want to write or send birthday card contact can be made - nothing!!!
fast forward 6 yrs ds loves his step dad have fantastic relationship - good family life, who crawls out from under rock on fb, yes father of year - queue promises of xboxes, visits, trips etc... and after 2mths of texts and calls (no visits he wanted to stay on our sofa or for me to drive 2 hours - me thinks not) i get the"i'm sorry such a let down, wont contact you or ds again" text so heard nowt since february so in revenge for him being the biggest waste of space and messing with ds head i got the csa involved after 11 yrs - dont want his money but thought balls to you messing us around - csa come back with £5 a week as he's on benefits!!! so im paying in tax what he contributes to our son.
then last week looking on ds's phone he's been texting again!!!! - if i had the money i woulf hire a hitman cos as far as im concerned he's using up precious oxygen!!!!!
so no - i dont believe every bio father has a right to be around!!!!
good luck with the baby - hopefully you have a supportive family network around you xx