You said you're not easily offended, so I'm taking you at your word and hoping that's the case.
I decided to email you about how upsetting and tactless I found your remark last week. I know you apologised, but it was in a kind of glossing-over-it sort of way. I thought I was ok with it, but I'm not.

I need to be able to regard the counselling sessions as a safe place, and now I'm struggling with that. I really hope you can understand why this is a big deal to me. Life at home is pretty ****** awful at the moment (the calm atmosphere didn't last long); I need this one place in my life to be ok.

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