Why did my ex boyfriend end his email to me like this?

So my ex and I have remained friends. However recently he did some stuff I did no appreciate. I emailed him and told him how I felt and I ALSO mentioned how I have indeed moved on with my life, it WAS relivant to the context of the email (since I even had a miscarriage from another guy last month). Anyway he emailed me back apologizing for what he did...but his last sentence said this : "miscarriage hu? ok"