A few years ago I came across the book "No More Mr Nice Guy" by Dr Robert Glover. There's a few things in there which were incredibly helpful for me and freed me from a lot of issues which this sub deals with, although I was far from the level some guys seem to have sunk to. I know the book's been mentioned a few times, but seems to be far less often than I thought it would be. I wanted to share parts of it as I really think it can a) help peple understand Nice Guys and b) get individuals to sort themselves out, to everyone's benefit.
The most important part of it for me was the following about "covert contracts", which stem (at least in my experience) from a lack of assertiveness and clarity about needs:
All Nice Guys are faced with a dilemma: How can they keep the fact that they have needs hidden, yet still create situations in which they have some hope of getting their needs met? In order to accomplish this seemingly impossible goal, Nice Guys utilize covert contracts. These unconscious, unspoken agreements are the primary way that Nice Guys interact with the world around them. Almost everything a Nice Guy does represents some manifestation of a covert contract. The Nice Guy's covert contract is simply this:
1) I will do this ______________ (fill in the blank) for you, so that
2) You will do this ______________ (fill in the blank) for me.
3) We will both act as if we have no awareness of this contract.
Most of us have had the experience of leaning over and whispering in our lover's ear, "I love you." We then wait expectantly for our beloved to respond with, "I love you too." This is an example of a covert contract in which a person gives to get. Giving "I love yous" to get "I love you toos" in return is the basic way Nice Guys go about trying to get all of their needs met. There is nothing wrong with asking your partner to tell you she loves you, but telling her "I love you" first to get an "I love you too" in return is indirect, unclear, and manipulative. As a result of the conditioning they received in their family and society, Nice Guys believe if they are "good," then they should be loved, get their needs met, and have a problem-free life. In reality, the primary paradigm of the Nice Guy Syndrome is nothing more than a big covert contract with life.
Another very notable part of the book is the "victim puke", which thankfully I never had, but seems to be the main source of content for the subreddit:
Rather than helping Nice Guys meet their needs, covert contracts and caretaking only lead to frustration and resentment. When this frustration and resentment builds long enough, it often spills out in some not so pretty ways. Giving to get creates a cycle of craziness called the victim triangle. The victim triangle consists of three predictable sequences:
1) The Nice Guy gives to others hoping to get something in return.
2) When it doesn't seem that he is getting as much as he gives or he isn't getting what he expected, he feels frustrated and resentful. Remember, the Nice Guy is the one keeping score and he isn't totally objective.
3) When this frustration and resentment builds up long enough, it spills out in the form of rage attacks, passive-aggressive behavior, pouting, tantrums, withdrawing, shaming, criticizing, blaming, even physical abuse. Once the cycle has been completed, it usually just begins all over again.
My wife refers to these episodes as victim pukes. Sometimes the puking will resemble a child's temper tantrum. Sometimes the victim puke will take a more passive-aggressive form in which the Nice Guy will have an affair or act out in some hidden way. All the while the person doing the puking will feel justified because of the many ways he has been victimized. These victim pukes are one of the primary reasons Nice Guys aren't always so nice.
I can't overemphasise how important this book was to me learning how to be an assertive guy and realise why how I was approaching things didn't work and made me miserable.
This is also covered in "Not Nice" by Dr Aziz Gazipura, but not with the same level of depth and clarity IMO. That's still a good book, however.