If you do teshuvah you are pure.
After seeing so much its hard to understand, but if you truly change yourself thats what happens- u change. Deeply. The point is not to stay pure. The point is to BE pure. Just BE- focus on now. Feeling guilty is only good when it leads you to do better. Dont feel sorry that u slid because it has the potential to turn you into a stronger and better person- better then the innocent girl u were in highschool. That is what life is about- facing real challenges and overcoming. And overcoming is what is valued. Not living in a bubble. Dont worry about your marriage. There is a time and a place for everything and it will make sense when you get there. Now just be the best u can- The harder the work, the more it is valued.