Mashallah. Very good example.
In general this is very true.
The only exception is for a small group of people who go to church/temple/mosque at least once a week (if not more).
In that kind of family environment, it is better to “combine and select one church” until the kids are small.
Do notice the word “combine” and not “convert”.
Marriage is a holy union for many, and harmonizing and uniting their church/temple/mosque will increase harmony in the home as well. Thus helping in improving the communication that adds to mutual love and respect.
For the Big-3 religions, there is no concept of “conversion” anyways. It is just the same Allah, the same paghambers and rasools.
However if someone studies with reverence other religions like Hinduism, Buddhism, Jainism etc. he/she will find the same rasools being sent by the same Allah swt.
So really it is the matter of husband or wife deciding to join his/her spouse’s church/temple/mosque.
All in love in harmony, with no force or coercion. Because Islam forbids forced conversions (however many Islamists do not follow this important edict).