I think I can make a rough guess about what your problem is. When your boyfriend tries to penetrate you, your vagina closes down in a tense way which bars him entry.

This is a common sexual problem among girls, known medically as vaginasmus, caused when your PC muscles clamp shut as a reflex action to anything that tries to penetrate the vagina. If that is the case, its involuntary and you'll probably have to see a therapist about it.

Just try the above suggestions and if they work, then all is fine. If they don't, avoid using force as it will make the problem worse and hard to treat. The problem is more psychological than anything with your body and is probably caused by your past sexual experiences (with the boy who repulsed you).

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