Relationship advice. Please help.

My bf and I have been together 12 years. Since we were 13. We both love each other but I feel he is to comfortable in our relationship to the next step. We have our general fights and petty arguments and sometime I feel as tho he doesn’t put me first, we have 2 kids together and I feel as tho I’m a single parent most of the time as he always finds an excuse to not help out or be home. I’m unsure on how to address the situation without causing an argument. Any ideas?