First, I’m not going to tell you to dump her. Everyone deserves a second chance. You have apparently found someone compatible with you and I’m sure as much as this hurt, the two of you have sat and talked about this and made things better. Otherwise you wouldn’t even consider marrying her, I hope! If she came back to you, then apparently the size factor wasn’t an issue. Sometimes people want to experience what’s out there before jumping the gun. If this was just a fling, I see no reason to not give her the benefit of the doubt and allow her back into your life. Her feelings for you probably outweigh it and I know she has to feel terrible for what she’s done to you.
Anyway, the main thing to remember, is PE is for “YOU”, not her. This is a journey for yourself. A bigger penis isn’t going to keep her, it’s you. If the two of you love each other, having a bigger penis isn’t going to make her love you more. This has to be something you’re doing to satisfy “YOU” first and in return, “maybe” it will satisfy her as well. I’m sure because she loves you and wants to be with you, the member you have now already does.
So if you can say I’m doing this for “ME”, then jump right in and join our fine community of PE’ers.
Best of luck to you, with everything!