Again I just don't see that inconsistency at all. The only thing she required at all times was total honesty. It's like in season one when the stuff came up about how Axe made money while her family and friends died dealing with the 9/11 attack. They were all pissed but she had his back. Why? Because she knew. Nothing was hidden.
She also does not give up a lifestyle. As we have seen, she has 50% of everything. It was always their deal. She is wealthy beyond measure.
I am not saying they don't get back together. They could, if they can get past the trust thing. But I don't think the split is fake or unusual for who they are as a couple.
Not sure I agree with the wealthy part. When Axe tells her they might have to survive on $300 million, she freaks out.
Every time they showed her this season, she was either shopping or watching her son's baseball games where kids get dropped off by helicopter.
Found this write up about Lara's character in Season 3.
https://www.refinery29.com/2018/04/195257/lara-billions-season-3-character-change-after-divorce