I'm 28, one daughter who is 7 years old and am single through choice. I have had relationships since I was 16 and they've all consisted of arguments and left me heartbroken and hurt trying to pick up the pieces. I like being single, I feel empowered being independent, I feel proud of the life I have with my daughter and my home is my sanctuary that I don't want to share with anyone other than my daughter. I realise I may not always feel like this but for now, I do.
My best friend has a husband, two children and is very family orientated - which is great because that's what makes her happy. However, she will always say comments such as, 'I know you enjoy being single but when will you start dating again?' 'I know you're happy being single but don't you miss sex?' 'I couldn't live alone like you, I would be miserable and so lonely'. etc. So I've always gotten the feeling she feels a bit sorry for me and thinks I'm putting on some act pretending I'm okay with being single.
Anyways yesterday we were at the park with the kids and she was talking about how her aunt has met someone at 60, and I said that's great! My friend replied, 'yeah I'm so relieved for her, I mean what a miserable way to live your life, single most of your days'. 
I instantly felt offended, not just for me but for every other single person, as if the fact she has a partner makes her life not automatically not miserable - and let's just say she has been at my house in tears over the past five years 100 times more than she's ever seen me crying.
AIBU to be offended by this comment or am I being overly sensitive?