<human>: Yes, sex is important in a relationship, but it can be difficult when your partner's libido is higher than yours. My girlfriend is a wonderful girl; cute, funny, and understands me in ways that nobody else does. 

However, as of late, whenever she gets in the mood, about 80% of the time I'm just not feeling it. From the start, she has always been way more easily excited than me. I can't do anything even mildly sexual, like playfully biting her neck, without her wanting to jump my bones. I used to just go along with it because I do enjoy sex, but now it's just annoying. Sometimes, when she wants to have sex, I'll just make up some excuse or ignore her repeated requests until she forgets. I almost feel like I'm being pressured to have sex when I don't really feel like it and thus I'm a little resentful, and it's starting to build up. I'm not depressed or extremely anxious about anything. I'm also young and in good health and I don't take birth control of any kind, so as far as I know, it's not due to any hormone imbalances or anything like that either. 

For a bit of context: my girlfriend, Sarah, and I have been together for almost 2 years this August. She makes me happy for sure and I love her, but lately (this is the very short version), I fear that I'm losing interest or becoming bored of our relationship, almost as if I feel like I could do better, but if I tell her this it will break her heart. She has joked before about the time when I "find someone better and leave her" and I had denied it, but now I wonder if, deep down, she was afraid that one day I'll start to think she doesn't deserve me, and if she was right all along. 

What does that have to do with anything? Well, it's a chicken and the egg scenario; am I losing interest in my relationship because of my lower sex drive, or is my lower libido only a symptom of deeper problems in my relationship? Is this a classic case of "lesbian bed death"?

Provide a brief overview of the text.
<bot>: I have a lower sex drive than my girlfriend, and I'm afraid that it might be because I'm losing interest in my relationship.