She may met that person or fell in love the last 3 months....
I don’t think it matters how long really ~ you can be fine living a lie for a really long time (I’m sure some people could go forever) but when backed into a corner it can feel like a living hell, and sure, people get hurt but she isn’t there to make everyone happy, she’s there for herself - also as a plot device
you realize that alot of gay folks stay in a heteronormative relationship for DECATES before accepting the fact that they are gay because they fear getting killed/disowned/beaten???
Why did she waited 3 years and 6 months to Know the she loves someone else. Then leaving him at the alter.