Advice

Gonna keep this short and sweet...I've been with my boyfriend six months. We moved in together in December. I love him and I know he loves me...the problem is sex when we have it its great but that's just it WHEN we have it. In the beginning we had sex everytime we saw each other like it was impossible to keep our hands to ourselves and when we were away we would always send dirty messages and pictures to each other but now things have slowed down...we don't "sext" and when we do its me trying to start it and he'll reply with "oh?" "haha ok" or something else like that. Same thing with being sexual ill start kissing him and its like hes not into it unless he initiates it...we've had this problem before and I told him how I feel (being scared of being denied basically) and hes told me he always wants to and to just go for it (but it doesn't help). I feel like hes bored with me or something..advice? Tips? Idk...something.