Of course it's normal, finances and the children are probably the biggest reasons for arguments in the household. Call the credit card companies tell them what's up and see if they can help you get back on track; cut up the cards; get financial advice; if you both have jobs, consider a p.T. Job....There's temporary agencies for not only office but labour type work(warehouses/logistics companies); if you have a home, consider selling it and acquiring a smaller home..
Sit down with her and have an adult conversation, "hon, what can "we" do to clean up our finances?" :)