Stuck between 2!

I broke up with my ex about a month ago because he never gave me his time. I would hardly see him, barely talk on some days and he would cancel dates sometimes because "something came up". Anyways, I ended that and about two weeks later, I start seeing someone else. It's been going really good. Despite his crazy job hours, he gives me his time and attention, which is something my ex never did. Well this morning I woke up to a message from my ex saying that he still loves me and misses me so much. He also said he's willing to change and won't mind losing sleep for me ( we both work crazy hours). He's said this before when we were together yet his actions didn't show any change. Now I'm sitting here confused... Should I keep going with the new guy? Give the ex another chance? Ugh! They both are special to me. I just don't know what to do 😟