Is divorce enacted by uttering phrases that could imply divorce, such as a suitor saying to his father, "If I hadn't married, I would have been comfortable," and "I've started thinking that I don't want her," knowing that these phrases were merely for expressing feelings and there was no intention of divorce?

Divorce occurs through an explicit utterance or through an implicit expression coupled with the intention of divorce. If there is doubt about uttering the words or about the intention of divorce with an implicit expression, then divorce does not occur; because the original state is the continuation of the marriage, and it is not nullified by doubt. What was mentioned in the question does not result in divorce, and one must disregard obsessive thoughts.