I don't want to ruin things between him and his wife!

Good afternoon my name is polite,am a lady of 27 years old.I am dating a man of 30 years old of age,we have been dating for 4months and this man is married with 2kinds.i knew he is married before we can start dating.i am deeply in love with this man and now i am pregnant for him.since i know he is married i dont want him to leave his family because of me,i think he is the only man who understand me since im having a cadioc condition and he makes me happy.i have a big dream with this man.may worry now is his family i dont know what to do because i love this man and i am happy about this pregnancy since we have planned it togather.i dont want to ruin things between him and his wife i respect them both.i am beeing driven by his love.what must i do since am pregnant and i love him