<human>: Could you distill the essence of the text into 1-3 sentences?

She's my first real girlfriend and we've been dating for 1.5 years with near to zero conflicts. We started becoming intimate fairly early on and would have sex at a high frequency untill about 2 months ago. It has become a scenario where there will be slight flirtation which seems satisfactory to her and she'll fall asleep. I feel really shallow when im sad about not having sex with my girlfriend but it makes me feel very unwanted /unattractive. For instance today was my birthday, she said she'd sleep over hinting that thered be a night time surprise but then once it had reached that point she simply falls asleep. I slightly confronted her about it and she said she wasnt feeling well nor feeling 'it'. Again I feel shallow about all of this but I cant help but feeling inadequate
<bot>: all of a sudden my gf seems hardly interested in me sexually and I dont know whether its okay to feel sad about it