For me its very important because I want (and am fairly certain God has it in my cards) to have a LARGE family. So if someone says his ideal is 1 or 2 kids, thats a problem. However, it wouldn't be a red flag that would prevent me from communicating with him because I don't think Men give it quite as much thought. Maybe I'm wrong.
I have to remind myself that not everyone is in agreement with the Church's views on contraception.
Peace in Christ :)
This is something that you could discuss with your future husband beforehand.
This is also something you should pray about, to seek guidance.
I don't know if this will answer your question but one thing is clear in my mind. That it is not for me alone to decide the number of children that I would have. It is between me, my spouse and God. For this reason, I answered "no ideal number" because I want to be open to having the number of children that God wants me and my future spouse to have based on a prayerful discernment of God's will for our family.
Having said that, I am praying to God to 'hurry up' in giving me my future spouse so that I could have the children that he wants me to have. Of course, I am kidding. While I pray and work on it, I leave everything to God's loving providence.
Have a great day!