baby #2 different dad help

Amanda
okay so don't judge , I got pregnant with my "friend" and he left once the test said pregnant , around 15 weeks pregnant I met my now husband and he has taking my son in through the whole pregnancy he was there , signed the bc and gave us his last name.  ANYWAY , our son is now 7 months old and we want a baby , the thing is I'm having a hard time getting pregnant , is it me or him ? both ? takes more time ???