Do not start a self-fulfilling prophecy. There is a syndrome of tunnel thinking - a person is fixed on one idea and pays attention only to those facts that support it. If a person constantly thinks of betrayal by another, he will notice only those actions of the partner that lead to betrayal. So he himself can push for this betrayal. The way out is to try to see other sides of the partner.
You may need to consult a therapist for this.
Not only rely on a partner. If a person is supported only by his partner, then betrayal will deprive the only support. The way out is to make acquaintances, communicate with colleagues, relatives. Another way is to expand the circle of interests, to develop personally and professionally.
Then after leaving or betrayal there will be more chances of "not getting stuck" in the situation. In addition, respect for one’s own interests allows one to respect the interests of the partner and not think that a person lingers at work because he does not love you.
Respect the interests of the partner. If you recognize the values of another person, it will be easier to give him freedom of action and trust his decisions. For example, he knows that he can hurt you, so he won’t stay at work.
But if he lingers or makes friends, this is his right, it is important for him.
Do not fixate on helplessness. If the betrayal happened, you have to experience the loss. But it is important to remember your own strengths and interests. Wounds heal, turn into scars, and scars help not to make similar mistakes in the future.
The experience of experiencing failures makes a person a person, nurtures a person.