Boyfriend/fake

So me and this boy dated for about a week then we broke up and he started dating my best friend then the broke up and he asked me to be his Valentine's I said yes then he asked her out agin a day after he dumped her because he still had feelings for me but he has dated  A LOT of girls he had a relationship for 3. Years she cheated everyone says he's a fuckboy and he said he had feelings for me should I belive him help me I'm only 16