Can't help but feel jealous

My wife and I separated back in April 2018. I met someone incredible just months later. She is older than me by 14 years and is a widow. Her husband died in November 2016.
I know she loves me deeply and always will but sometimes it's a hard on days like today when it would have been his birthday and she is hearting all the posts on Facebook about how he was the loveliest man ever and hearting all the photos people have put up of him. Am I being unreasonable? It's just so hard