Emotional blackmail is what exists when a partner tries to manipulate the other into doing something instead of actually asking that partner for what they really want.
But here is the thing: the person pushing against the behaviour might not even know that that is what they are fighting against because emotional blackmail is not something that is easily spotted. It component traits may feel repulsive in isolation, but it’s even worse when all the other forms of emotional blackmail are taken into consideration as a whole.
So while your partner’s behaviour at different times may not sit well with you and you may even feel the need to repel it on some occasions; it still takes a little more examination and observation to realize that it is a whole pattern rather than singular acts occurring independently at different times.
Once you figure out that your partner has a penchant for this type of controlling, manipulative behaviour, you should communicate with the partner and explain how damaging their behaviour is; and how it affects the relationship. The aim is to negotiate for a healthier, more open, more trusting relationship.
If nothing changes after this, do not hesitate to end the relationship because, really, no relationship is worth the cost of your emotional and mental wellbeing.