Taxes

I have been seperated for 15 months.
My husband walk out on me and my kids, leaving us a note. My questions are, can I file taxes as married filing seperate and claim my kids, and after I have filed tell him I claim the kids. He is on SS Disability and really if he files alone it will just be a wash with nothing owed and no refund.

Also, he has been giving me money every month for the kids, the last couple of months he gave me less and I think he is going to start playing around with giving me money. Can I draft a letter and have him sign and notarized it with the amount he will give me a month. Would such a letter hold up in court, if possible I would like to have my kids SS directly paid to me since I have the kids all the time. He comes around once every couple of months if their lucky. If I take him to court for support, I will get much less then he is paying me now, so I really dont want to open a can of worms for me. But, I would like to have some legal document with the amount he has agreed to pay.

Thanks!

If the children live with you more than half the year then you are eligible to claim them on your taxes, but if he also claims them it will likely trigger an audit of you both. Make sure you can document their time with you.