My bf of 3 years and i have a great relationship it only got better the past month when?

we finally introduced our kids to one another! however his ex of 5 years hares us still. apparently he was in one relationship after they decided to seperate and she ruined it for him because of her intereference. Shes a very scorned woman and shes been relentless with me yet i havent even seen her face to face more than one time. we laugh alot of it off but because they have a daughter they have to interact. she'll send him texts that are crude and nasty (both on a perverted level and just hurtful level). it wears on me but he gets upset and tries to tell her to just move on and etc etc, but that lasts a day or so. everything is great and our families are close but she is very very spiteful still and i know unfortuneatly theres no more he can do, but im wondering how i can just continue to ignore it...should i just take it in hopes that one day she'll move on? shes in her 40s and were in our 30s so theres an age gap of 8 years between her and my bf but youd think shes a teenager. can anyone offer advice of how i can outlast this woman and win this war? i get often depressed and steps away from going to her house and fighting her (and im NOT violent in the least)..i need help on staying focused and not falling into doom and gloom from this one toxic person...