I first learned that Jesus had brothers and sisters in a Bible study class taught by a Catholic priest in a Catholic church. When we were covering the passages mentioning Jesus’s brothers and sisters, the priest did not say something like ahem....an error there...they really meant to say cousins-—or better yet another whopper I’ve heard over the years-—those brothers and sisters were actually Joseph’s children from a previous marriage. Nope. None of that. The Catholic priest presented the Bible exactly as it is written, without any spin on it. That’s what all Christians should do IMHO.
I am sorry that was your experience. The defining document is the Catechism, and it speaks clearly.
It is certainly your choice to believe as you wish, but if the priest said what he said, he was in error.
St. Bede (d. 735) refutes both of the things the priest said, at Mark 3: 31-36.
The Bible, as written, was in several different original languages. It wasn’t until St. Jerome translated the books of the Bible into Latin. From there, we read the Bible in our own language. Without context, any number of interpretations arise. Without the teaching authority of Church, these incorrect interpretations give rise to false doctrines. As mentioned above, false statements about the perpetual virginity of Mary existed in the 7th and 8th century.
It may be worth your time to read this book (http://www.ewtnreligiouscatalogue.com/Home+Page/BOOKS/Bible+Study/DOES+THE+BIBLE+REALLY+SAY+THAT.axd) and find a good study Bible.
The Catholic Church has been teaching the fullness of Christian faith since the beginning. Any question you may have has likely been asked in the 2000 years since the Resurrection. I encourage to ask them! Ask your pastor. Also, consider reading catholic.com and ewtn.com.
Two of those half brothers of Jesus, James and Jude, wrote books in the New Testament.
I first learned that Jesus had brothers and sisters in a Bible study class taught by a Catholic priest in a Catholic church.
But to say Mary had other children is just adding to scripture, no scripture like that there.