One of the main criteria for entry into heaven or mukti is not specifically defined as non meat eating. I think Guru ji has made this rule specifically for kalyug where the quality of meat is on a decline and the cause of major illnesses.
All religions have some sort of similarity. At the end of the day survival on this planet is crutial if you are to earn your place in the darga. Vich duniya sev kamaiye ta dharge besan paiye.
Only Hinduism specifically says meat is to be avoided. However a person who is closer to God would not want to hurt or destroy another animal hence adding to their lekha. This is why a Sikh who is closer to God makes a personal choice to avoid meat.
If you have performed any form of sex (vaginal, anal, oral, etc), then that will be classified as a cardinal sin, which means that you are out of Khalsa Panth. In this case, you will have to go for Peshi (if you are still interested in being part of the Panth). The Panj Pyare will give you an appropriate punishment and they will make you re-take Khande da Amrit.
If you kissed, hugged, etc, even that is not allowed in Sikhism, except within marriage. In this case too, Daas would highly recommend you to go for Peshi. But, the punishment will be less severe in this case.
Do you plan to marry that guy? If yes, then I think you can go for Peshi after marriage. But, you need to confirm this with a Gurmukh Mahapurakh before following this advice.
Bhul chuk maaf
And you have not provided info to say there should have been more or less Gurus. What you provided was atheist views. So you were seen and continue to be seen as one because you refuse to recognize and accept Gurbani and Gurus for who they are. No one is an atheist for asking questions, it's the views you expressed here that make you one.