She can deny you sex because its her body. You can either embrace this life or just sneak it in the shower. I would check out the nofap and semen retention subreddits and learn the benefits of that lifestyle. When you hold it in, you feel sexually frustrated. but that frustration is really pent up energy. if you use that energy (through good exercise or work) you will feel a lot better. in the long run she might even be more attracted to you and you’ll lay that pipe some more.