All couples have different set of rules within the relationship, which may have been discussed, or may have just formed over time and not really reviewed. Good boundaries in a relationship keeps it safe, keeps the couple in their own ‘castle’ and stops someone or something forcing itself into the castle and therefore causing issues in the relationship.
If weak boundaries are in place, either thorough poor discussion or just gradually formed without review, then the chances of the relationship being challenged can become a higher risk. This might look like someone having a hobby that takes them away from their partner every weekend, and this leaves the partner feeling lonely and second best, or one or both meeting ex partners or friends of the opposite sex for intimate dinners or days spend together, which then leaves the other feeling unsure, jealous, or unimportant in that moment. If these things are agreed by the couple, they have talked though these different situations, risks, and both feel happy with the hobby or the other person taking their partner away, then often if well managed and reviewed, this can work successfully in a relationship.
But if this causes an issue, and either it’s not voiced, or if it is and their partner reacts with ‘you’re trying to control me’ the situation slowly erodes the relationship. The person left at home due to their partner’s excessive interest in their hobby may start to feel lonely, disconnected, and resentful. The person whose partner meets with opposite sex and is often communicating through social media, may start to create a worry that something might happen (an affair) that they are not good enough, that their partner would rather be with this other person than them. This creates a big disconnect and damages the relationship.
There’s not a right or wrong on these type of rules within a relationship, but sometimes even if it feels and seems okay, it doesn’t mean it’s a good way in helping the relationship grow and flourish. Constant checking your own feeling about what might be happening within the relationship, then talking it through, may then avoid it becoming too late to repair any damage caused.