First, do not make attacks, but explain your own needs.
Harsh criticism often infuriates the other person. For example: "What's wrong with you? All you think about is work, you never think about me!" or "You never call me, you never think of sending me a gift on holidays, you only care about yourself!" Goodness, who can stand being spoken to like that?
Let's learn how to "softly complain": point out your needs without blaming or attacking the other person. For example: "Honey, I really need your help taking care of the kids on weekends, but you've been working every weekend for the past month." or "I really want to be cared for by you, but it seems like I'm always the one calling to check on you, and I'm the only one who remembers to send you gifts on holidays."
Second, avoid generalizations and focus on specific behaviors.
A "hard criticism" would be something like, "You always break your promises and never take responsibility!" This would severely condemn someone's character and naturally provoke anger. A master of "soft complaining," on the other hand, would say, "We agreed to have dinner together tonight, but you made me wait for ages." In other words, they describe what happened, rather than stating a conclusion about their personality.
Third, emotions can be "talked about but not acted upon".
Most of the time, "talking the talk but not walking the walk" is not a smart approach. However, in close communication, when facing one's own negative emotions, the wisest approach is to "talk about" the emotions, rather than "act on" them. In other words, find ways to discuss your feelings with the other person, but don't actually put them into action.
For example, you could say, "I'm so angry I want to throw things!" After saying that, you've already expressed your true feelings, completely omitting the destructive act of throwing things.
Or, you could say, "What you just said is really unbearable, and I really want to run away." Right, don't just act on your feelings. You don't need to storm out; instead, stay and have a proper discussion with the other person about how you feel.
To give another example: "I have an impulse right now to yell at you to protect myself." Instead of actually saying hurtful things and blaming the other person, it's better to express your current feelings and motivations. This will prevent irreparable damage to the relationship and will actually enhance emotional communication between you.
While simply talking about your feelings won't make the problem disappear, it's a highly effective way to extend an invitation to intimacy. It's like handing the other person an invitation to connect, helping them understand your feelings and conveying the message: "My intention isn't to hurt you, but to get closer to you, giving them the opportunity to build a strong emotional bond."