Am I overthinking his password?

So I been seeing this guy for about 3-4 months. We’ve taken things pretty slow but we usually spend the weekends together. This past weekend I stayed the night at his house and I left something inside so I had to go back in. He has a keypad and I needed the code. I asked for it and he told me it was the last 4 of my phone number. I was taken back and asked why he done this, he mentioned it was easy for everyone to remember. We do not have any immediate plans to move in together, we’ve talked about it in the future but we’re talking some years. Why did he do this? Just an easy number to remember?

Am I overthinking his password?
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