Mahou Shoujo Ixia

Ixia is a half-angel, half-human magical girl. Her duty was to seal the soul of the devil. Her childhood friend, the protagonist, was helping her but the devil was accidentally sealed inside of him! To purify his soul, sex is required, but the devil is only interested in virgins. In order to completely purify the soul of the devil, Ixia magically regrows her hymen after every time she and the protagonist have sex.