It's nothing bad, I am just curious (as always) as I know young woman who said she is a single parent (group conversation few people chatted about their kids), but she also talks about her live in (for last 3 years) DP who she shares bills and childcare. He adores her kids which is great for them.
When does a single parent stops being a "single parent"? When you have a long term DP? Live in DP? When you marry again?