Is something wrong with me? Or my relationship?

Okay, so when my boyfriend and I first got together (a little over 4 years ago) I absolutely couldn’t keep my hands off him. We started dating in high school. We would have sex like all the time, even when we would leave campus for lunch. We’re now 20&21 with a newborn. The past year or so I have like no sex drive. I could honestly just go without sex forever lol however, I still use my vibrator sometimes when he’s gone at work. I’m just not crazy about sex anymore but idk if it’s something with my relationship like could it be we lost out chemistry? I absolutely love him but I never get turned on. I occasionally do but there has to be a significant amount of foreplay. Could it just be I don’t have sex drive? Or my relationship?