He keeps buying me sexy underwear??

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Ok so I've been with my boy for 10 months. He's never gave gifts until last month when we started college again. I was surprised he bought me something because he never bought me anything before. He recently bought me two pairs at different times of sexy underwear and he told me this afternoon he bought me something again. Why does he keep on doing this? He tells his roommate too but I think it's because his roommate's gf orders stuff online too and his roommate told him about it. I just find me being paranoid he's just using me for sex but he also tells me he loves me and we enjoy each other's company.