My husband loves his ex

My husband is having an affair with his first live from almost 50;years. We married 36 years and he has always had a torch for his ex. I found love texts on his phone 3 years ago and asked him to stop He didn’t as I found sone more months later. We had a big row and I thought it had stopped. She lives 8n a different country but visits where we live a few times a year. This has been going on 3 years will it end or should I leave. He says they’re just friends.