Husband is stressed

Amy
Hi all. Just found out I'm pregnant (1st time!)but I haven't told my husband yet. Hewas  apprehensive but having a second child (he has a 13 r old daughter from a previous relationship) because his ex has made c0-parenting difficult for him since day 1.  
He agreed to have at least one baby with me since it was a deal breaker for me when he proposed. (Together 8.5 years married 1.5 years) 
Now as my luck would have it his daughters mother has caused a huge battle this whole week and he's so emotionally stressed out that he actually cried today.  I'm afraid if I tell him I'm pregnant now he's going to just feel more stress as opposed to excitement. Any advice??? 
Thank you😊