Need a guys perspective, was he just looking for sex?

I've been casually dating someone for about six mounts. I haven't had sex with him but we hook up. Were not very intimate with each other emotionally but like to spent time together, at least i thought he did. In the past he's been pursing me but recently he seams less interested; hasn't been talking to me, putting effort or trying to hang out. He hasn't been texting me, which is odd since we rarely go more then a day without talking since we've been dating and he's always the one to initiate the conversation. The change was pretty sudden and Im confused what turned him off or how to get him interested again. Lately he's been hitting me up to hook up more and I've been the one trying to hang out. The only reasons i can assumed that could have caused this is the fact i'm not putting out, not into just hooking up, we've just been hanging out and nothing really fun lately, he perceived my asking to hang out as clingy, or something he got to know about me turned him off (i can be somewhat insecure and ditzy but i try to hide it). I don't want to lose his friendship because i enjoy hanging out with him and his group. I'm not sure if he's just in it for hooking up, but why would he waste all this time talking to me if i don't put out? What are some good ways to keep our friendship or gain his interest again or? Sexy facebook pictures? Hang out with other guys? Ignore his texts (We communicate mostly over text but i'm not sure how to get his attention by doing this when he's rarely texting me)