We are all on the same page as to what constitutes a mortal sin. There is no misunderstanding there.
The discussion in progress is about whether or not the person in question has committed a mortal sin. I concede that there is no way to know for sure, from our viewpoint, whether the sin committed was mortal or not. That is not for us to judge. However, we do know, for a fact, that the sin committed is grave, because of what the sin is.
Yes, I think we’re in agreement to this point.
I contend that we cannot tell a person, “Oh, since you didn’t really have FULL consent of the will, you don’t have to go to confession.” There were times in my past, when I spent a long time debating with myself whether or not I really had the full consent necessary for it to be mortal, to determine whether or not I had to confess it. It was fruitless, because there really is no way to know 100% for sure whether or not at the moment of the sin you had enough consent. It’s pointless.
I agree that “we” cannot say one way or the other and it’s inappropriate for “us” to advise anyone that their sin probably wasn’t mortal so don’t worry about it.
But this is the rightful role of a confessor, for someone who has an ongoing struggle with this sin. It is their place to advise as such. Not as a way to rationalise or make excuse, but to help a person who feels overwhelmed, overcome, and unworthy of God’s love and forgiveness.
Therefore, I think I can say without being unorthodox, “If you commit a grave sin, you should take it to confession.”
This eliminates doubt and confusion, and eliminates the chance that a person may end up not confessing a mortal sin or committing sacrileges by withholding it in confession or receive communion, simply because they are in denial about it being mortal.
Encouraging a person to discern whether it is mortal or not is fruitless, because depending on their personality they may end up rationalizing it into something it isn’t (which I have done before).
I make no comment in this post of this personal case of the OP, I am simply saying as a general statement that to tell a person that they don’t need to confess a grave sin because you don’t think it was with full consent is both fruitless and dangerous. After all, what harm is there in confession?
There is generally no harm in going to confession. But I would suggest there are a number of reasons why a confessor may choose to advise someone not to consider their ongoing struggles as mortal sins:
For someone who struggles with this and fails very frequently, they may end up in such a state of fear concerning whether they are constantly in mortal sin and thus immediate danger of damnation. Such is not helpful. Such may make them doubt the capacity for God to love and forgive them.
For someone who fails frequently, it may be impractical to get to confession as frequently as they fail.
For someone who thinks they are in mortal sin when they are not, it is a great shame if they forgo the graces of the most blessed sacrament because they haven’t yet had a chance to confess.
Also, it may be unhelpful for a person who fails very often to confess equally as often, since the act of confession may become rote and no longer afford them the peace and advice that they need.
Again, ONLY their confessor should advise along these lines.
Here is an article by apologist Jummy Akin discussing masturbation in some detail:
jimmyakin.com/2010/10/youthful-passions.html
In it he says:
*Finally, one might judge–if mitigating considerations like those named in the Catechism apply–that one is, in fact, not in mortal sin after a particular act of masturbation.
If this is true then one would be free to receive Communion.
However, people should not lightly presume this to be the case.
I would strongly advise a reader considering this option to have a discussion (or a few discussions) with an orthodox confessor or spiritual director to get a sense of when an act of masturbation is and is not mortal in a particular reader’s case.*