My friend was an alman when he married his daughter-in-law’s mother, who was a grusha. They could not be happier together.
A lady from my shul married someone who went meshugge and returned to his pre-gerus status; they obviously got divorced. She married a divorced man who became a BT after he divorced. They are doing just fine.
A rov whom I know and who many others here may know had to divorce his first wife because she declined in her level of observance (she had studied in a secular college because she needed the credits to go on for professional school and she studied all kinds of needless and unrelated kefira that caused her to go off). He married an almanah and they are doing just fine.