I'm married but the best relationship advice I can give to anyone is to KEEP OTHER PEOPLE OUT OF DETAILS OF YOUR RELATIONSHIP.
Men with own parents:
The bottom line to this is going to sound crazy but your parents are not going to consider all the factors of why you are with someone.
I.e how are you going to explain to you parents that your girl changed your mind on something by sucking paint and the epidermis off your pipe. The point is that their interest are always going to be different from yours. They just better hope that they raised you well but they really shouldn't be involved in what motivates and keeps the relationship going.
Men with the girls parents:
Same as above but with the shoe on the other foot. Be nice to the parents but also consider that in the back of their mind all sorts of crazy thoughts and speculations are floating around about what your doing with their daughter.
Men with friends:
Not every friend is equally yoked so keep them at a distance too with the relationship especially the ones that don't have what you got. You cant talk to your homie that is on a drought and lonely about the problems in your relationship. If you absolutely need to talk to someone then talk to the homie who has advanced in his relationship further than you have. i.e the friend that is married and has a someone decent relationship. Not the friend who cheats on his girl every other week. But also keep in mind that every relationship is different so no two relationships can really be compared.
Women with friends:
Your single friends will stop at nothing to try to sabotage your relationship. It is in the nature of the single woman to do so. I have been in several relationships where the girls group chat has given her terrible advice and influenced the girl to make poor decisions that have led to me leaving the girl and moving on. I have also been in situations where the same single girls from the group chat have tried to sleep with me. Like I said its just their nature and the jealousy is real.
At the end of the day this is all just advice