Sex advice

Okay, so on December 3rd my boyfriend and I will be together for 4 years. He is 2 and a half years older then me, he was a senior when I was a freshman. Now I am in college and he has been in college. 7 months into our relationship we had sex, which at the time I thought I was ready for it but I didn’t think it through all the way. I didn’t think that since I gave my boyfriend that new feeling of pleasure that he would want it all the time. Anyways, during 2 years of our relationship he bought me everything, smothered me with love ❤️ but it changed during this year it slightly changed. The attention he used to give me is slightly disappearing. He has been telling me for almost 2 years, he wants passion, love, he wants to feel loved. I try and I try to put the effort but for me it is really hard for some reason. I am attracted to him, I love him to death (even when he gets on my nerves) but it just seems so difficult for me to be creative and try new things because for me my fav position has been missionary but that is honestly where I feel the best. I feel very selfish and I really need advice and some ideas to try. Please help and please nothing hurtful. Every time we talk about it, we can never work it out.