There are certain situations which fall below the Bechira level, which – according to R’ Dessler – renders the perpetrator unaccountable for his transgressions. Nevertheless, putting oneself in a situation where one will fall below his level of control is enough to hold him accountable for transgressing.
Regardless of this, however, no-one has ever got himself off the hook in Beis Din for claiming that the sin he did was below his level of Bechira. בית דין של מעלה may accept that, but in our Beis Din, if you do the forbidden act after accepting the warning from two valid witnesses, we punish you.
There is one place where we find the Yetzer Hara defence in practical Halacha, although the parameters of this defence are subject to large scale debate in the achronim. The Gemara in Kesuvos 51b mentions a concept of יצרה אלבשה, which is enough that we consider – even in this world – certain situations as אונס, not רצון.
See also Kiddushin 40a, although not entirely relevant.
(Of course, this does not apply to disgusting people who have taivos and have no self control.)