What is Paul meaning of "husband" and "married to another" in Romans 7:1-6

“Know ye not, brethren, (for I speak to them that know the law,) how that the law hath dominion over a man as long as he liveth? For the woman which hath an husband is bound by the law to her husband so long as he liveth; but if the husband be dead, she is loosed from the law of her husband. So then if, while her husband liveth, she be married to another man, she shall be called an adulteress: but if her husband be dead, she is free from that law; so that she is no adulteress, though she be married to another man.” (Romans 7:1–3, KJV 1900)

Husband is Carnal Nature and wife is the mind

How do we know this?

“O wretched man that I am! who shall deliver me from the body of this death?” (Romans 7:24, KJV 1900)

Me meaning the inner man or the mind and the husband being the body of death

The law mandates that a wife cannot leave the husband - If she does this when the husband is alive, she commits sin and is therefore worthy of Death (Deuteronomy 22:22-30)

Therefore, we who are slaves of sin, married to sinful nature are mandated by the law to obey the same. We must commit sin, just as a slave is compelled to obey his master - to not obey is a sin!

Sin taking hold of the commandment - God's pure and Holy nature - has become exceeding sinful by doing that which God hates!

“For when we were in the flesh, the motions of sins, which were by the law, did work in our members to bring forth fruit unto death.” (Romans 7:5, KJV 1900)

“What shall we say then? Is the law sin? God forbid. Nay, I had not known sin, but by the law: for I had not known lust, except the law had said, Thou shalt not covet. But sin, taking occasion by the commandment, wrought in me all manner of concupiscence. For without the law sin was dead. For I was alive without the law once: but when the commandment came, sin revived, and I died. And the commandment, which was ordained to life, I found to be unto death. For sin, taking occasion by the commandment, deceived me, and by it slew me.” (Romans 7:7–11, KJV 1900)

Sin takes occasion by the commandment - the commandment that a wife cannot leave her husband - and forces me to commit all sorts of sin.

“Was then that which is good made death unto me? God forbid. But sin, that it might appear sin, working death in me by that which is good; that sin by the commandment might become exceeding sinful.” (Romans 7:13, KJV 1900)

I can escape only if there is no law - For without the law sin was dead (vs 8)

So what God does? - An amazing solution

“But now we are delivered from the law, that being dead wherein we were held; that we should serve in newness of spirit, and not in the oldness of the letter.” (Romans 7:6, KJV 1900)

God kills us in Jesus!

“Know ye not, brethren, (for I speak to them that know the law,) how that the law hath dominion over a man as long as he liveth?” (Romans 7:1, KJV 1900)

So once we are dead, now we can legally be bound to another - Jesus Christ. Thus we escape the condemnation of the law. But now being bound to Jesus, we are mandated by the law to obey Jesus and not commit adultery

“For the woman which hath an husband is bound by the law to her husband so long as he liveth; but if the husband be dead, she is loosed from the law of her husband.” (Romans 7:2, KJV 1900)

“Wherefore, my brethren, ye also are become dead to the law by the body of Christ; that ye should be married to another, even to him who is raised from the dead, that we should bring forth fruit unto God.” (Romans 7:4, KJV 1900)

The meaning of the words you ask about are the obvious ones. 'Husband' means the person a woman is married to and 'another' means a man who is not her husband.

So verses 2 and 3 mean

If a woman is married to a man, then she and that man are legally married for as long as he lives, and she is not allowed to marry someone else while he is alive. But is he dies, then she is allowed to marry someone else.

Paul is using this situation as an analogy to say that while the Jews were legally bound to the Law, the death of Jesus ends that bond, just as the death of the husband ends a marriage.