I wanted to ask a follow up question with regards to my ketubah. I grew up less observant than I am today. At my bar mitzvah and all subsequent aliyahs I received until relatively recently I used "Shimon ben Shumel" using only my first Hebrew name (which father does also). My ketubah was written with that name. It wasn't until my son’s brit milah, I was looking through some old documents, that I found out that my full Hebrew name is Shimon Aharon. Do I have to have my Ketubah fixed or does having used that name for so long validate the contract as that was the name I was known as.
A Groom or a bride who have two names and they are usually called by both, both names should be written in the Ketubah (Jewish marriage contract) and if only one name was written, the Ketubah is invalid. In a case where one is usually called by only one of his names and only that name was written in the Ketubah, post factum it is valid (Mishpat Haketubah by Rabbi Eliyahu Chaim Bar-Shalom gate 11, chapter 2, section 6). A name which was given as a baby and then completely forgotten, there is no need to mention it at all in the Ketubah (ibid. gate 4, chapter 3, section 7). In your case it seems that the Ketubah is valid because you were always called only by the name Shimon, and you did not even know of the existence of the second name which was completely forgotten. Nevertheless if you decide to start using your additional name regularly you may need to correct your Ketubah. There is also room to consider whether to use this name altogether after it was forgotten for so many years. Therefore it is recommended that you personally consult one of the great Halachic authorities who is an expert in the field of names and Ketubahs, in order to decide whether you should give up the additional name which was completely forgotten or use the name and correct the Ketubah, or leave the Ketubah as is and rarely use your second name.