I'm sorry to read that about your ds Lilac. What's wrong with some people. How/why would you make a 6 yr old feel sad and embarrassed. Sounds like she's made in heaven for WN 
I can understand your dc feeling they liked the set up when it was just you and them. You need a life as an adult as well though. Personally I think it probably helps you/us to have another adult that we care about. Even if it's just something casual. Your dc will always come first, but they'll grow up and form other attachments. In the meantime you need to take care of your own needs. You're self-aware enough to know you need to balance the two.
I felt a bit wobbly yesterday, precisely I think for this reason. Life's very organised, dc seem fine, I feel quite positive. But I feel a bit empty inside. I'm looking into starting a different type of business, which would be very people centred, but it would be a business though, not personal to me.
There's a great thread running at the moment about being happy to stay single. Lots of posters would like to meet somebody but not live together, wrap their whole lives up together. I know this would be my ideal, as like you Lilac I'm unsure if I have the emotional energy to give to a traditional relationship.
OhB Could you keep some of the toys, and give the rest to your mum/other family for ds to play with when he goes there? This way he gets some pleasure from the new things, but you're not confronted by a big pile of stuff reminding you of your ex every time you open the cupboard?