Woody182

My girlfriend and I have been together about 8 months, we started having sex after about 2 months. For some reason I associate sex and affection in general to the amount of happiness in the relationship. I.E. when we don't have sex I feel I'm doing something wrong. This has led to a lot of fighting as of late and surprise surprise even less sex. We're both 21 and I know I'm not in the relationship for the sex but for whatever reason this continues to happen.
I don't really care about the sex deep down I am not quite show why I bring it up so much. My question is this, is it normal to gauge a SO's level of happiness with their desire for affection?
Thanks in advance

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If I fall in love, will you forgive me?
If I lose my way, will you choose me?
If I change my mind, will you change me?
-Smashing Pumpkins