I.
The Muslim is obliged to guard his tongue and not swear too many oaths, because swearing too many oaths leads to committing oneself to doing things that are not obligatory, whether they are actions or offering expiation or committing the sin of swearing a false oath.
The religious texts instruct the Muslim to guard his oaths and they condemn swearing oaths often.
Allah, may He be Exalted, says:
{But guard your oaths. Thus does Allah make clear to you His verses that you may be grateful} [Al-Ma’idah 5:89].
Al-Baghawi (may Allah have mercy on him) said:
What Allah meant is refrain from swearing oaths; in other words, do not swear oaths indiscriminately.
End quote from Tafsir al-Baghawi, 3/93.
Al-Qasimi (may Allah have mercy on him) said:
The wisdom behind the command to reduce oaths is because when someone swears oaths by Allah in every situation, trivial or serious, his tongue will become accustomed to that, and he will have no respect for the oath in his heart, so there is no guarantee that he will not swear a false oath. Thus the oath will lose its value and purpose.
End quote from Tafsir al-Qasimi, 2/192.
And Allah, may He be Exalted, says:
{And do not yield to any contemptible oath-monger} [Al-Qalam 68:10].
Ibn Qudamah (may Allah have mercy on him) said:
It is disliked to swear by Allah excessively, because Allah, may He be Exalted, says: {And do not yield to any contemptible oath-monger} [al-Qalam 68:10].
End quote from Al-Mughni, 13/439.
II.
If you estimate that the number of times you broke your oath could be as many as one thousand, and the oaths were about many matters, and the situation is as you described, that you have sworn very many oaths and it is difficult to expiate for them by fasting or any other way of offering expiation, then what appears to be the case – and Allah knows best – is that you can follow the view of Imam Ahmad, as mentioned in one of the two reports from him, and it is the official view of the Hanbali madhhab: you can offer expiation once for all the oaths you have sworn in the past.
Imam Ahmad (may Allah have mercy on him) was asked: What about someone who swore oaths regarding various matters, or swore an oath about one matter many times, in one gathering or in several gatherings?
He said: If he has not yet offered any expiation, then offering expiation once is sufficient.
End quote from Masa’il al-Imam Ahmad wa Is-haq ibn Rahawayh, 5/2439.
Ibn Qudamah (may Allah have mercy on him) said:
If he swore many oaths about doing many things, and said: By Allah I will not eat, by Allah I will not drink, by Allah I will not wear, then there are two reports concerning that. One of them says that it is sufficient to offer expiation once for all of that. This view was favoured by Abu Bakr and al-Qadi, because it is expiation for one type of deed, so they are interconnected, like the hadd punishments.
According to the second report, he must offer expiation for each oath. This is the apparent meaning of the words of al-Khuraqi, because it is an oath and he cannot break the one oath by breaking another oath. So for every oath he must offer its expiation, as they are separate. Abu Bakr said: The correct view is the first one.
End quote from Al-Kafi fi Fiqh al-Imam Ahmad, 4/195.
Ibn an-Najjar (may Allah have mercy on him) said:
Whoever swore (multiple) oaths based on one motive, even if they are connected to different actions according to the more correct view – such as saying: By Allah I will not eat, by Allah I will not drink, by Allah I will not give, by Allah I will not take – if he has not yet offered any expiation, then offering expiation once is sufficient. This was stated in a report from Ibn Mansur.
End quote from Sharh Muntaha al-Iradat, 11/106. See also: Kashshaf al-Qina`, 14/415.
It says in Nayl al-Ma’arib bi Sharh Dalil al-Talib, 2/426:
Whoever breaks an oath, even if he swore a thousand oaths by Allah, may He be Exalted, and has not yet offered expiation, offering expiation once is sufficient, even if it is for different deeds, such as if he said: By Allah I will not eat, by Allah I will not drink, by Allah I will not wear… End quote.
But what you should do, whatever the case, is guard your oaths in the future and do not swear many oaths, whether you are telling the truth or lying, whether you want to fulfil them or break them.
And Allah knows best.