Why would you go to a church whose teachings you clearly don't agree with?
Lots of reasons. The church changed over time and you're not ready to cut ties yet. You disagree with the church on social issues but agree with it theologically and its practices are part of your culture. You're geographically isolated and this is the only church you can go to. You believe the church is the only source of valid sacraments so you're locked in. You're trying to make a family member happy.
Or maybe it's entertainment. She's not a Christian at all, she's a moral therapeutic deist. She goes to church to hear about how much God loves her, listen to some elementary moral teachings about easy problems, and maybe sing or listen to some soft rock songs about loving God and God loving her. You know, lifting up her hands and crooning all five verses of "Jesus Is My Boyfriend." When she finds out her boyfriend has standards and expects certain things of her, that's too much.
The most likely reason, though, is she made it all up. That's why there are no details, and why she refers to "the Christian church," which is something Christians only do when they're emphasizing the ecumenical nature of Christianity. We're usually pretty specific regarding which brand of church we attend.
I skimmed the responses because I'm not going to read them all, but I got MATI when I saw atheists recommending what used to be excellent mainline denominations because they've been hopelessly pozzed. First, because they're atheists and don't care at all about this woman's spiritual health, they just want to keep her on Team Abortion. Second, because they're treating denominations like they're interchangeable, like if a certain McDonald's serves cold fries you can just go to another. And finally because the denominations they suggested were once very fine churches, and I still resent their subversion. Luther, Cranmer, and Wesley are rolling in their graves, except Cranmer didn't have one because he was burned at the stake and dumped in the Thames.