Guy still loves his ex from over four years ago?

I've been talking to this guy i work with for a few weeks now. We've hung out quite a bit and kissed and stufff. Me and my ex of over one year ended things about 4 months ago. My guy and his ex of over 2 years ended things about 6 months ago. He also has another ex of over 2 years before his most recent one. We both work with the ex of 4 years and lately i've noticed that she texts him every night and they talk all the time. We talked about it and he told me he likes me but doesn't want to get too serious yet because it's hard for him to forget his ex because she was his first love. it bothers me that he's living in the past so much and i want to help him get over her but i get so jealous whenever he's in contact with her! he told me last night that he just wanted to forget about her but i feel like he's not even trying. i told him to forget about her he needs to get out of contact with her and stop talking to her all the time! i dont know what i should do... i really do like him and we have a lot of fun together.. i think we could be really good together but i'm really cautious because i do not want to get my heart broken again. i feel like i can help him get over her if he would just let go. is it stupid of me to think that if he keeps talking to me and hanging out with me i can help him get over her? i know i'm competing with someone he loves but.. idk. if anyone could give me some real advice on what to say to him/do. i really don't want to get hurt. thank you :)