kay ... soo ... im only 13, so i might not have had the best experience for this type of problem, but ill definately give it a shot
soo ... this guy is helping to bring a baby into this world with a married woman, just to seek vengance against you just because you've moved on?! if he still loved you, i doubt he would go and have a baby with another lady. he doesnt sound too nice at all.
sorry your heartbroken honey =[
feel better soon
lotsa love <3