Bleeding during sex

Hi everyone, I’ve been sexually active for about six months now. When I lost my virginity I didn’t bleed. But then I bled almost every time, unless I get very very wet. Sometime it’s the stretching that tears my skin (which is understandable and preventable) but sometimes there’s no sign of damage on the outside. We thought he might have damaged the inside with his nails but after when we tried again with his nails cut it was still bleeding. Unless there’s apparent external damage it doesn’t hurt. It also only tends to bleed when he fingers me. If he only penetrates me it’s usually fine.

Should I see a doctor about this or is it just because I’m not lubricated enough? But that doesn’t explain the lack of pain?

(These all occur when I’m no where near my period so it rules out period blood)