Guru Sahib says that husband and wife should be "one light in two bodies". for me, this means that my husband and i must share our spiritual life. and happily, we do.
it's great to have someone to wake up with you at amrit vela, to help me to understand gurbani, to go to the gurdwara together, do seva together, and to discuss religious, spiritual, and political issues that a non-sikh might not understand.
there are so many little things, like if you're amritdhari, you can't share food from the same plate as a non-amritdhari... my husband and i love to share food, i can't even imagine if we weren't allowed to!
i guess it just depends on how important a role your faith plays in your life. for my husband and i, it's central to our relationship.
but like you said, religion isn't as important for young sikhs as for the older generations, so my personal feelings aren't going to make sense to everyone.