It is hard to differentiate and diagnose vaginismus vs. vulvodynia without doing an exam.
It is possible that you have either, or both. Vaginismus is the contraction of the vaginal muscles that prevent penetration, and vulvodynia or vestibulodynia is pain at the vulva or vaginal entrance. You for sure have pain at the entrance, and that pain could be because the muscles are tightening up. Vulvodynia can also be from hormonal changes, or nerve proliferation at the vaginal entrance.
It is possible to have a very thick hymen, and when your partner tries to penetrate, you are feeling pain from that tension, and possible tearing of the hymen.
Most gynecologists are not very experienced in vaginismus or vulvodynia. So as long as they can get the speculum in and complete their exam, they will probably say, “you are fine”.
Seeing someone to assess the muscles, like a physical therapist, or a specialist in vulvodynia would be my next suggestion.
Or…try a home dilation kit. See if slow progressive dilation over time helps. If you do have some vaginismus, the dilation should help treat that. And if your partner is very wide, you would need to keep dilating up to a size that is as big as him.