Fiancé of 4 years lying to me

Been together with fiance for 4 years, we've been living together and engaged for 3 years, I'm a 42yr old male and shes a 40yr old female. I just caught her lying for a second time. This time she said she was at her parents but she was actually was helping her ex-boy friends mother find a new home. A year ago I caught her talking to him several times for 20 min, she says they didn't talk in a while and wanted to see how things were, apologized and said it wouldn't happen again. Too me this seems like low level bs, but I don't need to accept or tolerate it, and really have no proof she isn't hiding anything else. I'm not gullible, but really do believe she isn't cheating on me, is a good person, and we are happy, all which is why I am with her. We aren't married, have no kids, and I own the home. I'd be willing to work through this, but is this something I should break up or take a break over, or when is enough enough? Your time and advice is appreciated!

Personally, as a female, I have contacted my ex, when I was bored. Just to see if he still was wrapped around my finger. I don’t think there’s anything serious you should be worried about, but I’m not 40, so I wouldn’t know how your fiancés mentality works. Just, go with your gut feeling. If this is truly bothering you, ask her for a break. See what she does. If she comes back, If she fights for your relationship, you know she loves you.