FIrst of all... I really dont believe in their being more STRONGER break up spells. The spell is as strong as you make it. I mean I can break up two people with two figure candles break up oil, and all of that. But if you are not addressing the issues head on...or dont address the issue why they keep getting back together especially if another person is helping them get back together. I did use lucky mojo's break up bottle spell kit fixed with dog hair cat hair, and whatever else it comes with. The first time I buried the bottle in a cemetary. The next kit I buried it at my ex boyfriend's house since she was living there with him. I put it as close to his bedroom window as possible. The one thing I added to the break up bottle was I added rotten organic milk (like straight from the cow milk although I dont think it makes a difference what kinda milk you use) vinegar, and asafoetida.
One spell I made a heart out of clay to represent my ex boyfriend's heart. In the clay, I wrote (target's heart) and like a zig zag line down the middle of the heart to represent broken love for the person,. Then I wrote the target's name down the candle (wick to base) and then the command "remove love for (name here) from (target's heart)" So I wrote "remove love for kelly from brandon's heart" for this example. I dressed a black free standing candle with asafoetida (banishing and removing) licorice powder or calamus (to control their heart) red pepper, and poppy seeds. I used some separation oil, and clear cut powder or oil. I put the candle in the middle of the clay heart. Stabilizing it so it didnt fall over in the heart. Also, I made a petition basically stating what i wanted to happen like " As this candle burns, Brandon removes all love for Kelly from his heart. His heart is blackened, and cold towards her. " and what ever else you want to say. Or you can just keep it simple such as saying "Remove the love for Kelly from Brandon's heart" I would burn the candle over a course of 9 days rather than just one day. I started this on a Saturday on a waning moon. Once the candle was done, I would burn the candle down on the 9th day. The candle should cover the heart in black candle wax, and I disposed of it by throwing it to the west in a crossroads breaking the clay heart, and not looking back. I did this step because I know with my ex boyfriend the reason why he would keep going back is because he still felt love for her. Once the love was gone for her, he stopped going back towards her.
Before I go on, I wanted to say that you know your ex boyfriend better than her. Use this to your advantage. All the spells I did I hit him on an emotional, physical, and mental level. Emotional with the heart spell above. When I said get into his mind, I increased the emotions and things he already thought about her with a skull candle. I increased my target not being attracted to her and not wanting to be around her. For this you need to know your target, and I knew my ex-boyfriend extremely well since I was with him for 3 years.
And through divination I was able to see what his true view of her was. Also, you can always hook the girlfriend up with another guy. Through divination you need to find out what her perfect guy is. Attract them towards each other, and make her really like him.
I think what made me successful is that I never relied on just ONE spell. The important part is to be realistic, and dont put such a time frame on things. You are dealing with people's emotions, and most people in love do not have one fight, and thats it. Most people go with their heart despite what their mind says, and they will stay in a situation sometimes because they don't want to be alone. You literally need to develop a game plan and change the game plan accordingly. Sometimes you get lucky and it only takes one spell, but to say that it is only going to take one spell is probably why people get led to disappointment. You really have to ask yourself "how much effort, time and yes money do I want to put into this situation"
A few spells I used lemons, but I dont want to type a novel LOL so if you want you can message me for that, and how I did the skull candle spell and a few other resources. I will gladly give them to you. Just PM me

Thank u St. Martha for everything you have done on my behalf.
Thank u St. Elena! I appreciate your great help.
Thank you St. Peter for opening the gates&roads!