"It is good for a man not to touch a woman. Nevertheless, because of sexual immorality, let each man have his own wife, and let each woman have her own husband. Let the husband render to his wife the affection due her, and likewise also the wife to her husband. The wife does not have authority over her own body, but the husband does. And likewise the husband does not have authority over his own body, but the wife does.
"Do not deprive one another except with consent for a time, that you may give yourselves to fasting and prayer; and come together again so that Satan does not tempt you because of your lack of self-control. But I say this as a concession, not as a commandment. For I wish that all men were even as I myself. But each one has his own gift from God, one in this manner and another in that." (1Corinthians 7:1-7, NKJV)
This last verse, as well as verse 2, helps explain why Paul said the married state wasn't a sin, but it was a lower spiritual state. Interestingly enough, Jesus gave similar reasoning to the disciples when they questioned His condemnation of easy divorce laws:
"For there are eunuchs who were born thus from their mother's womb . . . and there are eunuchs who have made themselves eunuchs for the kingdom of heaven's sake. He who is able to accept it, let him accept it." (Matthew 19:12)
Paul, in 1Corinthians 7, merely makes it clear that yes, indeed, those who aren't able to receive it (this teaching) aren't sinning when they marry to avoid burning with passion:
"But I say to the unmarried and to the widows: It is good for them if they remain even as I am; but if they cannot exercise self-control, let them marry. For it is better to marry than to burn with passion." (1Corinthians 7:8-9)
In some of the verses you cited (1Corinthians 7:32-35), Paul explains his reasoning behind encouraging celibacy, in that married people are more divided in their interests in serving God compared to the devoted celibate single man or woman. In verse 26, he mentions the "present distress" as a reason not to marry, but that can't be deemed as a universally applicable reason that applies to all Christians at all times, but rather it applied in particular to the Corinthians who receive this letter roughly around 55 A.D. He still pointed out that he wished to spare people worldly troubles resulting from becoming married, however (verse 28), which is a universally applicable point. Jesus also did warn that those women who are pregnant or have to nurse children during the great tribulation to come would wish they didn't have those burdens then (Matthew 24:19), which is at a distinct time in history to come. Perhaps one way to look at this comparison would be to compare people giving different amounts of money to charity: If two men with equal incomes, equal wealth, and equal family responsibilities gave different amounts to the poor, such as 10% versus 15%, the latter has been more righteous, assuming he maintains an equally good attitude about his giving. But the one giving 10% can't be deemed a sinner (compare 2Corinthians 9:6-9).
It's necessary also in this area when the married state is compared to the celibate state to avoid thinking the married people are sinning, especially if they simply have trouble controlling their natural sex drives lawfully. A single man burning with passion, even if he isn't actually having sex with women (Matthew 5:27-28), sins badly, but a married man and woman making love to each other don't sin at all. So the problem with the married state stems much more from all the special care and attention that a wife or husband needs from the other partner, as well as their children, if they have any, which takes away from time that could be used for serving God directly, not from the physical sex act itself. But marriage shouldn't be looked down upon. After all, didn't the author of Hebrews write in chapter 13, verse 4:
"Marriage is honorable among all, and the bed undefiled; but fornicators and adulterers God will judge." (Hebrews 13:4)
God also uses analogies and parables to explain spiritual concepts to us earth-bound men and women, which compare material things to spiritual things so the latter are more understandable. At least some anthropomorphisms (attributing human characteristics to non-human creatures and beings) are in this class as well, although if the Book of Revelation's description of heavenly scenes are taken at all literally, the "God is shaped like a cloud" view has to be discarded regardless of how much scholarly research over the centuries can be cited to back it.
God is a family, in that the Godhead is presently composed of the Father and Son, which I believe is a real relationship, but it's on a higher plane than our own family relationships. Similarly, as you pointed out, God said He was married to Israel, and Christ will marry the church. The use of these terms constitutes what's been called "analogical predication," that the same word "Father" for God doesn't have quite the same meaning as "father" as applied to a man, but there's still some similarity. When these terms are used in Scripture, their meaning is neither identical or the same (univocal) nor is their meaning totally different (equivocal), such as when "cape" is used to refer to a piece of clothing and to a geographical feature (i.e., "the Cape of Good Hope" in South Africa).
So I think part of the explanation for the use of "marriage" in Scripture when it concerns God's own relationship with people, such as His condemnation of Judah and Israel's adulterous unfaithfulness in serving other gods besides Him (Jeremiah 3:6-13), is to make God's feelings and thoughts more clear to us humans.
For example, when Israel worshiped false gods using idols, Jehovah felt betrayed like a husband does who finds out his wife is having an affair with another man. This is more understandable to average people reading Scripture in getting across God's sense of anger and betrayal about Israel's false worship practices than explaining something more abstract, more removed from our own experiences, or highly ethereal would accomplish. Now obviously, the marriage of Christ and the church won't result in physical sex (Luke 20:34-36), but it will be a wonderfully close relationship between God and saved humanity (Ephesians 5:21-32; Revelation 19:6-7). Hence, the word "marriage" in such a context doesn't have quite the same meaning that it has for the fleshly union among men and women on earth today, but there is at least some similarity.
So God used the term "marriage" relationship to communicate to us His desired close relationship with humanity. He even planned the design of the physical creation to make His will and goals for humanity more understandable by creating Adam and Eve as separate beings who would come together to produce and share the greatest earthly pleasure there is (Genesis 1:28; 2:23-24), to make His (desired) relationship with us more understandable to us, despite our intrinsic intellectual limitations.
Hence, God is a "Father," that is, He relates to His creation using a masculine persona, which makes Him more understandable to us humans since we have "fathers" also, rather than being a more removed, ethereal "One" or even "It." (True, modern-day feminists object to this Scriptural analogy, but they need to conform their beliefs to Scripture rather than trying to rewrite Scripture to fit in with their human reasoning). Here the Muslims err by rejecting the idea that God has a Son or sons (John 3:16; 1:12-13), which denies the ultimate purpose for God's creation of humanity (Genesis 1:26-28; Ephesians 4:13; Hebrews 2:5-17)