Rock and a hard place...

So, me and my boyfriend have been dating for 3 months going on 4... Lately Its like my feelings for him are fading. Fast. I told him but he is determined to stay together. My ex / first love came back into my life wanting me back. (We broke up because we were young and didn't know anything) I'm 17 and my mom just put me on birth control because I told her that I was ready. My ex said he wants to be my first because he doesn't want me to be hurt by anyone else and because he loves me. My current bf is always talking about sex and it gets tiring. I honestly don't know what to do .... 😞😞😞😞 help ... please...