Most of the time when an ex asks for time/space, they are not necessarily asking you not to contact them. They want you to back off from trying to get them back, stop talking about the old relationship, stop putting pressure, stop being needy, stop fighting – or whatever it is that they want you to stop doing. It doesn’t always mean they want you to go away.
If you just stop contacting them, it will set off an alarm because your ex will not know why and may not understand your reasons for suddenly distancing.
Asking your ex what they mean helps clarify things. You might be surprised that all your ex wants is for you to give them a break from talking about the old relationship or pushing to get back together.