Am I being insecure or overthinking?

Me and my daughter’s father has been on good terms trying to make things work. He received a text from another woman one day. I didn’t trip about it but a week or two later I stayed over and watch tv the same woman that texted him. Name was logged into his smart tv. So I checked on his ig to see who she was ever pic he post she likes. So I finally asked he told me she brought him food to show condolences from the passing of his mom that she’s just a friend. But I still don’t trust it. Every time he posts it she’s the first one to like it. Is this something I should leave alone? Am I overthinking it?