Hey crack!
Fact: men can't have one sexual partner in life and can't stay with same sexual partner for life. That's proven.
Problem: If you continue cheating, you'll get used to it. You'll have everything a man needs outside home and you'll be satisfied with your gf because she gives you what a man needs from a friend. You MUST force yourself not to cheat, that will let you see what you really need as a man. That will start a confrontation with your gf and either she will change or you both will split apart quickly.
Solution: Do an introspection. Define what you feel for your gf, what you want in the future, what you like, how you see yourself in 5-10 years. Do not cheat anymore. I mean, while you are studying yourself. Even if you need to brake with your current fuck buddy, that's ok. There will be plenty of how spread eagles later but now, you need to think. Put everything in a balance and see wich side is heavier. Fix everything and stay with your gf, or stay single fucking everyday. Cheating for 5 years and then stoping doesn't count as an alternative. That's not fair for your partner. All you've done is already unfair for her but do not make things worse. And I understand you as a man. That's why I can tell you, THINK. You are not forced to be with anyone and your child will be yours always.