I have a question, I am German. I have entered United States with the visa waiver program / ESTA that allows you to be 3 months as tourist in the United States. But I stayed more than 3 months in US Now i live in Spain. it has been over one year since I left US, I want to know if I pass the border by car would they know that I overstayed because when I left the country I left by plane and they did not stamp my passport. so, that means my passport is clean because it has nothing showing when I left. The question is that What Border Patrol sees when they scan the bar code on your passport. I also got married in the time I stayed in U.S. What could I do to try to enter U.S again.
The US probably knows about your overstay.
Check your passport at https://i94.cbp.dhs.gov. They probably recorded your exit based on information passed to them by the airline when you flew out of the country; that's how it's supposed to work, anyway.
Your past overstay makes you ineligible to enter the use the Visa Waiver Program. To enter the US again, you are supposed to apply for a B-2 visa.
The US never stamps passports on exit, so the absence of an exit stamp in your passport doesn't help you at all.
The fact that you got married while you were in the US is not particularly relevant, but if your spouse lives in the US, or is a US citizen, you may have a harder time proving that you don't intend to stay in the US. This would make it harder for you to get a B-2 visa or to pass through passport control when you enter. If your spouse is neither a resident nor a citizen of the US, then this is of no concern to you.