Why would my ex still text me when he has a girlfriend?

My ex and I broke up only 2 months ago... we were dating for 8 months but we broke up because I have a bad temper and attitude.. after two weeks he already had a girlfriend. later he broke up and now he has a new girlfriend... he text me saying how I've been and if I was busy I didn't respond.. we have a weird history we kissed when we were little playing spin the bottle I was his first EVERYTHING we've been knowing each other since the age old 15 now we are 18 and one night he asked if I still loved him again I did not respond..... I still love him dearly but have to much pride to talk to him.. why does he still text me why can't he erase my number like I erased his and how could he move on so quickly.. or is their something holding him bak