Husband purchased porn from ex gf

So I found out that my husband purchased porn from his ex girlfriend while I was pregnant with our child! I found out about it a couple months ago and confronted him about it when I found them saved to his laptop while I was searching for photos of our baby. He said it wouldent happen again but I'm really struggling to move past it. There is so much free porn on the internet, why would he feel the need to buy it, especially from an ex gf... he didnt have a reason when I asked him, and i was too hurt to press for answers while caring for a baby.