I need to help my best friend...

She’s been in a relationship for almost 3 yrs, the guy is gold to her. I’ve known both of them for the longest time. Anyways, she came to me about a problem. I’ve noticed it with her over the past yr or so but I don’t get in anyone’s business. I always keep to myself. She came to me crying cause her and her bf almost broke up. I feel bad cause I really don’t know what to tell her cause I am the complete opposite of the way she is. She’s very insecure and jealous, it’s pushing him away from her. She’s asking ways of how she could feel less insecure and jealous. This guy will not hurt her in any way. When they first got together she found porn in his phone and I think that got to her also. Some people it does/some don’t. I do believe it could hurt someone in a relationship for many reasons. But that’s one thing she won’t let go, I feel bad cause of the way she feels about herself and she’s very very pretty. What do you ladies have that you could help me with. I need some advice. :/

Me, I’m not the jealous or insecure type. I’m just very chill as you can say.

But I know a lot of women are jealous or insecure about something and it gets the best of them.

How do you all deal with it or how have you helped a friend out?