Any advise

Sonya
Hi there,
I am posting on behalf of a friend who's in a bit of a dilemma so she asked me if I could help her out.. No abusive comments please 
Well what it is that's she is married to her husband who's already married they have spent three years together now she has just found out she's pregnant with his kid. The problem is that she said to her husband to leave his ex if he wants to move on in life as as he promised to her because he's still living his ex..She is still waiting for that to happen in this case as she is pregnant would it be right for her to have the baby or not this is her 4th child whilst on the pill she become pregnant after three miscarriages so it could be hard for her to become a mum again he wants to keep it but she is 50/50 She is in a complicated situation.. Any suggestions or advise