Complex sentence: In some cases couples living together do not wish to be recognized as married, such as when pension or alimony rights are adversely affected, or because of taxation consideration, or because of immigration issues, and for many other reasons.
Split into simpler sentences: In some cases couples living together do not wish to be recognized as married. This may occur because pension or alimony rights are adversely affected; because of taxation considerations; because of immigration issues, or for many other reasons.