Perjury is not sex, obstruction is not sex, abuse of power is not about sex. It's important to understand that none of the proposed articles include allegations of sexual misconduct. The president is not accused of marital infidelity because such conduct is essentially private. When circumstances require you to participate in a formal court proceeding and under oath mislead the parties and the court by lying, that is a public act and deserves public sanction.
Perjury is a crime with a five year penalty.
We were told there are three pillars to the rule of law. An honest judiciary and ethical bar and an enforceable oath. And this is why the president's lying under oath is so serious. It is an assault on the rule of law. It cheapens the oath, it is a breach of promise to tell the truth.