Have ever experienced this?

My ex had a routine doctor's appointment near me. She called and came over. We spent some casual time just talking about random stuff. I was hungry, she insisted on cooking. Oh man, the way she moved in that kitchen, in the house... She knew where everything was and what to do. She knew because she set that kitchen up 2 years prior. I didn't have to explain anything like I do with other girls.
Some strange emotion rushed into me. I walked away to compose myself. I walked away because if she had seen me like that it would have started some conversations I was ready to have. Strange feeling to miss someone who is right in front of you.
I wonder if she did it on purpose.