my (24M) girlfriend (24F) said something to me over text message that's really gotten under my skin and I'm not sure how to handle it

I have a bit of a backstory here so bare with me, my girlfriend and I have been together for almost 3 years now and the entire time she's been the one to initiate sex EVERY time, we'll go weeks without sex and not saying anything about it and it's always her Protean to get us to have sex. We've had issues with her not getting wet enough and not being able to get her off, but we've worked that part out. I've always thought that she just says all the right things, and she knows what I like the most, so it's a win win. <br><br>We had sex yesterday and she initiated, and we went through our usual routine, and I couldn't get her off. So I asked her if she was turned off by something about me, or if I had gained a little weight, and that maybe I should start working out. But she said "no baby you're amazing, it's just that I don't find you that sexually attractive".<br><br>This has gotten under my skin, because it seemed like a pretty fuck you thing to say to me, I wanted to tell her to maybe find someone else then, but I know that's not the right thing to do, and I don't mean it. I just want to know how to approach this with her, because I'm still in love with her and all, but I just feel like shit knowing that she doesn't find me attractive, and how should I go about this with her. <br><br>Edit: typo fixed