when your asked to get married and when your partner wants to move out due to childrens attitudes

I'v been with my partner for 1 year but when we first started dating he asked me to marrie him I said yes I was so exited , he said we'd get married on the 10/10/10 and well he's changed his mind he now says we will get married when we do he left me for a while as he wanted a relationship so bad with me then said he didnt know what he wanted ,, I stuck around and waited on him now he's with me and he lives in the house with me and my children , but he's now saying that he will move out if my kid's continue to not do as they are told and if they don't go to school ,, I'm thinking this is so wrong as he took me on with my children he shouldn't be thretening to move out all because thing's don't go right that's all part of life ,, i'm wanting to marrie this person so much and love him ever so much but it seems we want diffrfent things not sure what to think or say