SEX ..and How do you know if your cervix is closed after miscarriage ??

My bleeding has stopped 6 days after I passed the tissue naturally.. my last blood test hcg level was at 900 (also 6 days ago)

How do I know when it’s safe to have sex again? I am not looking to start ttc again but my sex drive is back and I want to be sure it’s okay to act on my urges☺️