Starting to question my marriage

My husband and I work, he works in construction M-Sat from 8am to 6pm while I work in fast food M-F 10am-4pm while we work my mom takes care of the girls they are 2 and 1

Ever since out first daughter turned 6 months he stopped helping me all together. Before he would help me bathe, change diapers and even feed her without asking me he would just do it on the spot. But now 3 years have passed and he's become a lazy  parent. He doesn't help me with anything when it involves the girls. I brush their teeth, bathe and play with them. As soon as the girls see him come through the door they go crazy calling him "papa". He would sometimes lift them up and give them a hug and a kiss.

I completely understand wanting to unwind but this is just pure laziness. He takes off his shoes, washes his hands and goes straight to the sofa. He doesn't talk to the girls, unless one of them brings him a book to read in that case he would, but after he is done he'll give them the book back and return his full attention to the television or phone.

If I ask him to change the diaper of one of the girls he's answer is something like "I'll do it in a few" so I end up changing since I see that he's not moving or he'll ask me to get the diaper and wipes for him so at that point I'm like F it all I'll do it. And the brush the girls teeth he says that I do a better job that's why he doesn't bother. 

I hate this so much, I'm letting myself go. My depression keeps coming and going. I'm super stressed, I just can't anymore. I've had multiple talks with him and he says that he is willing to help more but the never does. The way I see things going this is not  going to improve and I see us going our separate ways. I've tried everything that i can and it's not making things better. He always tells me that he would never leave me but I honestly doubt that. I'm trying to be strong for the girls and put up a happy face but I'm reality all I want to do is just cry nonstop.

Again I'm really sorry for my stupid rant. It's all over the place but I just need it to vent for a bit.