"The ascending aorta is typically about 5 to 8 centimeters (or close to 2 to 3 inches) long and about 3 to 4 centimeters wide. Its diameter can be considered dilated if it exceeds 3.5 centimeters, and an aneurysm is generally defined as a diameter greater than 4.5 centimeters. - Source: Cleveland Clinic

You mention your ascending aorta is measuring "3.6mm" do you mean centimeters? A centimeter (cm) is larger than a millimeter (mm); specifically, 1 cm equals 10 mm.

My husband's ascending aorta measured 4.6 cm when his primary care physician referred him to a cardiologist. The cardiologist wasn't too concerned given my husband's excellent health and no family history or prior history of aneurysms anywhere in his body therefore he recommended monitoring and a rescan in 1 year to determine growth (if any).

With your prior history of aneurysms and stoke you are likely in a high risk group and should seek advice and regular monitoring from a cardiologist who specializes in aortic disease. My uneducated guess would be that a '3.6 cm' ascending aorta is closer to the normal size and not in the danger range however determining rate of growth via periodic CT scans would seem especially important for you given your history ... a cardiologist should guide/advise you on this.