Does committing sins and feeling useless blame and fear of falling into disbelief—especially when afflicted with obsessive-compulsive disorder—affect the validity of the marriage? And is what the questioner is experiencing considered disbelief?

The matters in which you fell were not mentioned to clarify the extent to which the Sharia prohibits them. Generally, all people err and repent; for "All the children of Adam are sinners, and the best of sinners are those who repent." The sinner must repent and do good, as Allah Almighty said: "Turn to Allah with sincere repentance," and "Seek forgiveness from your Lord and then turn to Him in repentance." Allah warned us against despairing of His mercy, for "Do not despair of the mercy of Allah," and "Do not despair of the mercy of Allah. Indeed, Allah forgives all sins." These are whispers from Satan, and not all sins take one out of Islam, unless they are disbelief, and committing sins does not remove the wife from the husband's marital bond unless it is apostasy.