@William @lungs
You guys suck because:

While picture William projected is a distinct possibility it is not the rational or constructive one to assume.

Ignore the OP request of socionics based evaluation of the persons motives. Instead you give personal experience, gut feeling, common sense, one brush paint all evaluation. Socionics is intended to better that, and what are you doing here anyway.

Who is two timing? Obviously not physically, and LSI is not an ethic to likely to go "I definitely have feelings that are to be heeded to for this person so everything else is a farce or immoral mess" so you are judging by a wrong template.
The LSI is obviously not head over heels toward for him, to run in to his arm disregarding all considerations, but are Ti base ever?
The "common" sense you judge by is that if you really want the fruit don't let it hang lest it will spoil or someone else will take it. So she is not really interested in him. Except that that common sense is offensive to EIE LSI romantic values as far as I understand them, while situation of the waiting may actually be a better start for their relationship.
By "the book" they live for the diagrammatic spin with commitment and fate being in value.

Is it unfair for her to suggest for him to have relationships with expiration date while she has hers? That is suggesting symmetry and so upholding fairness. Regardless of whether it is actually ethically and emotionally realistic for her or him. Certainly sounds like Ti kind of logic/daftness(?).