**To me, it does not matter that much. If Mary and Joseph had a celibate marriage**
Catholic believe that Joseph and Mary had no other children.
Not ALL Catholics.
Some of us believe what is written in the Bible.
The Bible specifically mentions Jesus had brothers and sisters. I first learned this in a Bible study class taught at a Catholic church by a Catholic priest.
The Bible also mentions that Mary was a virgin at the time of her conception of Jesus. But there is absolutely no mention whatsoever that she remained a life long virgin or that her marriage with Joseph was not consummated.
The Lord commands us to be fruitful and multiply. Physical intimacy between a husband and a wife is a precious gift from God, not an act of defilement. There is no reason to believe that this gift was denied to Joseph and Mary. The idea that Mary was always a virgin and there was never the gift of physical intimacy between her and Joseph is strictly conjecture on your part.