It was evident in The Last of Us Part II that the relationship was strained. This is what happens if you believe something without confirmation.
A husband or wife might stay with their partner if they suspect their partner is cheating. However, things will completely change if they confirm that their partner cheated. This is what happens if you believe something without confirmation.
This is what happened to Ellie.
She believe Joel was lying, but she didn't know for sure. The birthday trip when she appeared happens until the end where it writing on the wall called the Fireflies liars. In the second flashback, you can easily see that there's something wrong between Ellie and Joel. At the end of the flashback, she questions Joel again in a way that she didn't believe the lie that he told her.
This is what caused her to confirm her suspicion.
It's not that simple.
People lost their lives on their way trying to get to the Fireflies (Tess, Henry, and Sam), and she nearly died several times trying to get there with Joel. She wanted her journey to mean something after all the struggles they have been through.... and yet it amounted to nothing. So she has every right to be upset after dealing with so much guilt.
None of that make her less hypocrite.
A wife suspecting a cheating husband is not remotely the same thing as being a potential cure for the entire planet, if she cared that much, she should have called joel right there after the hospital.
She decided to accept a badly veiled lie to live a better life so she is a fucking hypocrite, it is that simple, sorry.
Hell even in those situations where a wife stay with a cheating husband we call those women hypocrites because they decide to accept a bad situation to gain something else (that could it be financial security or not being alone without an husband).
Did She needed several years to realize that people lost their life for their mission and get mad? Even more contrived shit, she should have been furious after the hospital scene because those death were still super fresh.
The moment she accept the lie because it was the more convenient thing to do, she become an hypocrite and has no right to be mad at joel (or at least not that much).
She is an adult by the time she yells at joel, she should know why a parent would never give up a daughter, that alone should give joel a big ass excuse for what he did (hell she kills an entire town to avenge him).
I guess we agree to disagree on this one.
I can understand her being mad but in that cutscene where jeol confess she act completely clueless and that shit was hilarious, she was smart enough to know that the only way joel could take her out from the hospital was to kill everyone, but she act like surprised pikachu...