Religion? NO!
Denomination? Maybe.
No one should deny faith and violate their conscience and conviction to win over a potential spouse..... a Christian should not deny Christ in order to encourage a cute Jew to say "yes" to his proposal. A Christian should not deny Christ to so that a pretty Atheist will say 'yes." A Buddhist should not LIE and say she accepts Jesus as her Savior and agrees with the teachings of Lutheranism so that some handsome Lutheran will be more apt to propose.
But I think changing denominations is possible. Indeed, I think sometimes people just grow up in the denomination of their parents, and it's GOOD to think about that as an adult. Indeed, many denominations have Confirmation Classes that encourage people to not just inherit their parent's denomination but to claim such AS THEIR OWN. I think it CAN happen (indeed, often does) that a "mixed" affiliation may BOTH examine their own Christian beliefs - and may well find they find a "match" together.
MY own experience....
My beloved grew up in a tiny, very conservative Reformed (Calvinist) church, a member of the Orthodox Presbyterian Church. She comes from a long, long, long line of Scottish conservative Reformed Christians. Her family remains there. And she today remains VERY thankful for that upbringing. However, before I met her, she had "issues" with some things there: Limited atonement, "double" predestination, etc. (issues also felt by many in her family).... and her music degree lead her to really appreciate the worship forms found in Orthodox, Catholic, Anglican and Lutheran churches.
As we began to discuss marriage, we BOTH said we don't want to be split on this... we don't want to go to separate churches. I went to her church several times, I LOVED the closeness of the members, the great pastor, the strong pro-life and pro-morality stance. But I missed the liturgy, the Sacrament, and the great comfort I felt in Lutheranism. She went to my church several times. She found the same small church closeness, the same great pastor, the same pro-life stance. And she loved the liturgy and worship. SHE decided she wanted to learn more, and the pastor held a "Adult Confirmation" Class for you (he doesn't do classes, he meets individually with interested persons). He met with the two of us 8 times or so. She came to really like the view of the Sacraments and found that actually her own views were more in line with Lutheranism than with the Reformed faith. She was Confirmed.
She has an uncle who is a Reformed pastor. When she told him she was going to a Lutheran church, he hesitated and said, "Please tell me it's an LCMS church." She said "yes" and he responded, "Great! It's a good church."
Did she change denominations to marry me? NO. She changed denominations because she found one that she agreed with more and that "fit" her better. NO repudiations of her former one (she holds it in great esteem) just found a better "fit." And I'm 100% sure she would have been Confirmed regardless of whether we got married or not.
Now, had she been uncomfortable with Lutheranism, what would have happened? Who knows.... maybe I would have embraced her church. Maybe we would have ended up with some VERY conservative Anglican church (there are 2 in our area). Who knows.
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