If i marry some1 who owes arrears in child support with this become my obligation too. Can child support come after my assets?

If you marry someone who owes child support these are arrears that accumulated prior to your marriage. Therefore, they should not be any connection to you for your spouse's obligations. However, it is possible that if there is any modification of child support going forward, your income may be part of the income that is looked at in computing future child support. But there is no connection to arrears that I can see.