Ex girlfriend.

My SO looked up his ex girlfriend on his Facebook. We have had a problem before where he text her but I said no because that wasnt right. He hasn't text her since then. But every now and then on his Facebook I see that he has looked her up. Doesn't message her, just looked her up. Does that mean anything? Yes I do snoop, but only because of the one time he did talk to her first on Facebook and then he got her number. He doesn't have it anymore. But again does it mean anything that he felt the need to look at her profile?