Ladies I need advice... Mother in law issue big time!

This has been a reoccurring issue since about 3 months into my relationship and my husband and I have been together for 2 years now! His ex is so stuck on him still after she made her choices to cheat etc.... He broke it off with her and wants nothing to do with her. His lovely mother though is so absolutely in love with his ex that not only does she still talk to her she hangs out with her... Buys her things... Takes her to get her hair done etc! The issue is he ex has tried contacting my husband numerous times and is now having my husbands mother watch her son.... Cuz she just doesn't have anyone else to do it..... Rightttt...... Well I have had many go arounds with his mother and his ex because of her trying her stuff. I have told his mother that I will not have a relationship with her if this continues and my husband and I even went as far as not talking to his mom for like 8 months. Well we now made the decision to move onto his parents property to help take care of the land etc because of the fact his dad has broke his back and had a shoulder replacement and just can't do much anymore. I guess moving here was a bad idea! Cuz she comes to bring her son every Friday for his mother to watch then when pick up time comes about she freaking stays here for like an hour or more to "just visit" so the other day his moms phone was messing up and I was handed her phone to try to help her figure it out and she walked out of the room.... Well her messages from the ex were pulled up.... I saw my husbands name so naturally I continued to read..... I know to some that may be wrong but if you saw your husbands name on messages from an ex you can't tell me you aren't gonna check that out! Anyway she was expressing to his mom how she has tried to move on but can't she will never be over him and she hopes things can work out between them two even though he is married and his mother was freaking condoning this! Saying she hopes things work out the way they should! What the actual fuck! Ladies what do I do because I have to remember I am a mother and jail time is not an option....