If a couple has a harmonious relationship, this is a hurdle that can be overcome. Problems are resolvable. It is critical to take care to not permit such issues to become a divisive wedge between a husband and wife. Some ideas were suggested in earlier comments, and I can think of others. Get creative. Ask a Rov, not just for a psak, but how to settle the issue.
It is recorded from quite a few gedolim and tzaddikim of earlier generations, including both chassidishe and litvishe persuasions, that one can justify increasing chumros relevant to Pesach, but not to accept kulos. However, one must be able to distinguish between a halacha, a halacha based chumro, and a minhag. The differences, especially as would pertain to a couple with differences in practice are significant. A good Rov would know the differences.
AYLOR (Ask Your Local Orthodox Rabbi)