2 yr old Maltese and potty training

Question
I have a 2 yr old Maltese and he is not neutered yet. I thought when I first got him he was totally potty trained. He would go out when he's supposed to and "go". Then one day I noticed almost every corner in my house was marked. So he was going outside as well as inside. I started putting him in a crate when I was away and then letting him out when I got home and the first place he would head to is outside to go to the bathroom. I don't really have this problem with anything other than urine. If I get him neutered will that help or is it too late? Is there anyone (experts) that can help. I do not want to ever get rid of him but I'm going to have to get rid of my carpet in my house. Help!

Answer
he is getting lazy and very naughty lol!
he is running the house, neutering may help calm this behaviour down but i would try to avoid it.
A crate is a good idea when he does it give him the look show your dissapointment say no firmly and place him outside do this each time he does it i dont expect you to watch him 24/7 lol
but please try this if it doesnt work neutoring may be the way forward but let me know how you get on
plus you need some urine stain and smell remover from your pet shop regular soap etc will not erradicate the smell so the scent is still there and attracting him to it
Good luck!