Should i love or let go?

me@ my bf split in oct last yr he really wa the love ov my life,my best friend my lover, i trusted and believed i him 100% then out of the blue he leaves me and our5 kids sending me a tex 3wks later saying he wanted a fresh start, he got bak wiv his ex who i neva gave a second thort about in the 6yrs we wa 2geth, dunno wot to do confused bout him at the mo any help?