astrology is an evolutionary process. the potentiality archetype can be constant if its connected to saturn, but more often than not there are certain multilayered evolutionary processes going on from year to year, month to month, day to day, saturn return to saturn return, jupiter return, solar return, etc.
even if venus stays in the 12th you get Different shades of it. a complete blockage should only last in most cases until venus in progression surpasses a negative position, or a transit phase somewhere ends.
for example if you have venus in progressions in 1st house then it would be a different story of the 12th. it would be 12th-1st reciprocation. then there are also tertiary progressions .
here are some tools to help you see when you would have a better love phase.
long-term transits to venus related houses. you would have to wait for these to clear out. for example saturn moving in to the next sign for some people might make a difference. also check dipositers of planets not just rulers.
progressions. if venus is opposite 6th which is a significator of conflicts then there would be some kind of problem for a while, but then when it moves to a different aspect range there would be new kinds of connections. also looking at things like progression ascendant or other positions that would help along the process. there are different types of progressions, but the most common formula is day for a year. it starts calculating the days after your birthday.
solar arcs: sometimes theres information about the thematic content a particular concentration of thought in them. it also acts as another chart not only a transit. it is another type of progression based on the movement of the sun with your natal sun. its more movement of ego based.
solar return: when natal venus is in the 12th and SR venus also lands in the 12th then it will be a dead calm. lunar return would be a month-to-month type of emotional reciprocation towards the situation when one cares and when one doesnt. usually in SR if someone is looking for love it'll show in 5th or 7th. if its 5th and 7th with negative aspects it might not come through.
vimshotarri dasha: timetables are also about themes, and when a particular planet is activated with receptions this might indicate a more austere or aesthetic period. these try to sum up the entire more than one year phase under a certain "planet". this is because of the rhythmic patterns of the sky, but several subperiods are needed for timing and outcome. the planet will be activated or you'll run in to it, but its more about the lingering stream that it produces. its not exact and too precarious by itself, but when added to transits+chart it denotes a severity and cluster.
its all interconnected. if there is a phase somewhere in the chart it'll probably also point to it from a different perspective with another technique. one has to only look at the natal+transits to get an idea if they look closely at the details, but they wouldnt know the proportions of it.
now. astrology is sometimes about getting a grip on the thematic lessons its not a wish fufillment type of thing, but if you find the right steps the path will change. it goes up and down and around, so you will be paid back if you notice everything else.