All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
The basic principle is that your husband is free from committing adultery, and it is not permissible for you to accuse him of that without evidence. The accusation of adultery is one of the very serious matters that may result in the implementation of the punishment for slander [i.e. accusing someone of Zina without evidence], which is eighty lashes, as Allah Says (what means): {And those who accuse chaste women and then do not produce four witnesses - lash them with eighty lashes and do not accept from them testimony ever after. And those are the defiantly disobedient.} [Quran 24:4]
What is Islamically required is that a person should think good of a Muslim and not have a bad assumption of him; this is even confirmed in the case of the spouses as Allah, Glory be to Him, established between them this strong bond, which He called in His Book the “Solemn Covenant”, as He Says (what means): {... and they have taken from you a solemn covenant?} [Quran 4:21] As for doubts, they are from Satan; so, one should strive hard in repelling them and not get carried away with them or achieve some of their effects, such as this oath and the like.
What happened between you and your husband does not lead to the rulings of Li’aan. Li’aan takes place between the spouses if the husband accuses his wife of adultery or denies her pregnancy from him.
One of the conditions of Li’aan is that it should be before the ruler or someone who acts on his behalf, such as the Muslim judge.
The basic principle is that the bond of marriage still exists between the spouses until proven otherwise.
For more benefit on Li'aan, please refer to Fataawa 432001, 428203, 429916, 193277, 122944, 88978 and 84301.
Allah Knows best.