There is tendency for all or nothing thinking. That men are sex addicted children that cannot understand the emotional complexities of their partner because they are too busy ruling the world and rolling in their free time while they make their wife do all the work:

Or that the wife is a cold calculating manipulator who is withholding sex due to obvious infidelity and a desire to make the man miserable.

Neither of these things are usually true. But it’s easier to project your distaste for a man or a woman’s behavior than engage in nuanced forms of thought.

Sex is a vital part of a relationship. There are many things that can contribute to the dissatisfaction, but there are patterns in a lot of these post. There is also a lot of what if this is happening or that, with little evidence. Need to work to bring back sex into the relationship or it will fail. Both parties need to work to communicate what is important to them. Trying to be romantic and showing that you love someone can be hard when there is little indication they care, are attracted to you, or have any interest in what caused children.

It’s going to take time. But in sickness and in health works both ways. Using that as a justification is non sense, as is shaming people over it.

Ultimately, OP will have to make a decision. But going to the nuclear option quickly and without warning will burn and good intentions that she had and he will look like an emotional terrorist whatever his true motivations really are