Sex after postpartum

I’m 3 weeks postpartum, I had a c-section and had my tubes tied after they got our baby out. My c section went great and was back to doing my daily activities after a week. I’m wondering when I can get back to having sex. My last OBGYN told me they say wait 6 weeks bc you can get pregnant right after having a baby... but since my tubes are tied it makes me curious if the 6weeks applies.