IS IT OKAY TO BE WITH SOMEONE THAT STILL HAS FEELINGS FOR THEIR EX?

Well i just start dating this guy name Travis, & well hes soo sweet & everything but i asked him if he still had feelings for ex girlfriend and he said he did. So i got upset. Ever since that i been having second thoughts about our relationship. Like what if we stay together,, but then he decides that he kant over her && he breaks up with me. Im gong end up getting hurt && i dont want that to happen. Every night we talkk about us && he says that he wants to be with me && that hes getting over her little byy little. But its hard for me to belive that. Should i just let him go && move on or just stick aroundd and see where this leads to?