Having sex is completely a decision of that particular woman. It is her will and you must respect it. You cannot expect her to have sex against her will. If the sexual desire has been too much you can try masturbation. To an extent the sexual tension is relieved by masturbating. Do not use pornography. It can cause erectile dysfunction in future. If the sexual tension is causing poor concentration, irritability, you must meet a sexologist.
Next Steps
Kindly meet a sexologist and discuss your problem in detail. Do regular physical excercise in morning, do not use pornography, etc are some instructions. You can masturbate if you're too much sexually tense.