Going Through A childish and Disastrous Relationship

Me and my girlfriend are now been dating from last 2 years, but i have never felt an urge for intimacy from her side in these two years, its not that i jad ever forced her, no , i have well communicated her to feel relaxed until we make it. But on the other side its its intense emotion and feeling of urge that i go through, the peaks i ieel amd then a sudden drop because she isnt feeling so.....i feel as if i am not being loyal to my feeling, as if i am not respecting my feelings. I can help myself with a video as earlier, but from the day i came into relationship it makes me feel if i ll be cheating her if ill see others naked. And i have seen Karma has done things in my life, so i scared of it. Is there amything i can or i should. Because it has been a long time and i have not felt that emotions from last 2 yeears. It makes me lonely and then i feel irriitated but i dont shout or complaint her ever for this. I have tried to convey this to her, but she forgets and i dont think she ever had any second thought on this matter.