My ex boyfriend admits he loves me but iv already moved on but still kinda like him. HELP!!!?

Im only 13-keep in mind. Well im dating this guy whos nice. But my ex saw us together and i guess he got jelouse. Tht night (tonight) he txted me he loved me snd felt incomplete. Hes NEVER shown thus side of him before,but i do like my current boyfriend. Plz giv me advice on wat to do.