As ESV Study Bible states in the note on the passage of Malachi 2:16 (bold is mine), “The Hebrew text of this verse is one of the most difficult passages in the OT to translate, with the result that the two main alternative translations proposed for this verse are strongly disputed.”
So, to try to 'square the circle' we are now to start from some anchors, as the starting line of a sprinter.
1 - The verses 13-16 of Malachi 2 form a logical group, with the one and the same context, namely, God is against who divorce from his wife (except in the case of God’s lawful reasons to divorce, namely, adultery, or exposed/quasi-exposed ‘nudity’- see an answer of mine, on the passage of Deuteronomy 24:1 What does the phrase "uncleanliness in her" refer to in Deuteronomy 24:1?).
2 – God considers the marriage as a legal covenant (Mal 2:14), derived from the original purpose of Him. ESV Study Bible Note (bold is mine): “[…] this passage is clear in its recognition that the biblical standard for marriage derives from the creation account (see […] Gen. 2:23-24) which establishes the covenantal nature of marriage. (Jesus when discussing a question about divorce, began with creation (Matt. 19:3-9.) Malachi starts from this creational base: he refers to creation (Mal. 2:10), calls a marriage a covenant (v. 14), refers to the oneneness of Gen. 2:24 (‘union’, Mal. 2:15), and reminds the community of the purpose of marriage (‘godly offspring’, v. 15). The man who would divorce the Israelite wife of his youth (perhaps even for the purpose of taking a pagan girl as his wife) thus commits a grievous offence: he violates the creation order, he breaks his covenantal relationship with his wife – and, in so doing, he deeply damages his character (‘covers his garment with violence’). But the impact of divorce reaches far beyond the individual, for divorce has a ruinous effect on the vitality of the whole community (vv. 13-15) and on its ability to fulfill its calling as God’s holy people.”
3 – The wrong behaviour of the man at issue in these verses must have to do with the goal to marry a woman as a replacement (younger?) for the original wife (‘wife of your youth’ [נעוריך אשׁת], twice in Mal 2:14-15).
4 – This behaviour impelled God to refuse every gift or offering the man at issue would give to Him (Mal 2:13; compare also the same concept exposed in 1 Pet 3:7).
Once we have got these solid conclusions we are ready to face the difficulties of this text.
As my habit, I now transfer here the Hebrew text of Mal 2:16, morsel by morsel (from 1 to 16), without the Masoretes’ diacritical system points (except that on the sin/shin letters, to distinguish between the two).
כי־שׂנא –  For-he hates or I hate
שׁלח –  to send out > to divorce
אמר –  says
יהוה –  Jehovah
אלהי –  God of
ישׂראל –  Israel
וכסה –  and- (who) covers
חמס –  (with) violence
על־לבושׁו –  on-garments of him
אמר –  says
יהוה –  Jehovah
צבאות –  (of) hosts
ונשׁמרתם –  and-you guard yourselves
ברוחכם –  into-spirit-of you
ולא –  and-not
תבגדו –  you deceive.
First Difficulty: “Who hates? A man (his original wife) or Jehovah (the sending away > the divorce)?
The text (morsels 1-2 above) leaves both the options open. Why? Well, maybe the most difficult thing for the slavish followers of Masoretes’ tradition to accept is that the Masoretes didn’t try to improve - systematically - the Hebrew text upon which they did stick on their diacritical system. It is historically proved that they ‘crystallized’ some Hebrew texts of the TaNaKh, which yet contained – regrettably - some errors (happily, the vast majority of them we – today - are able to correct through the utilization of textual criticism, or by comparison with cognate languages, context, or other linguistic disciplines).
Furthermore, the Masoretes, did not try to restore some linguistic original functions possessed by the ancient Hebrew tongue, such as the cases system, as well as the chronological factors inside the Hebrew verbal forms, or the univocal and fully independent personal pronouns, and so on.
Then, what about the first option (a married man was the hater)?
Consider an interesting comment in the Commentary of John Peter Lange (bold is mine):
“The LXX, Vulgate, and Luther, construe this very differently as a permission of divorce; ‘If thou hate her put her away’. But this is inconsistent with the context, which condemns divorce; it is in opposition to the law which permits divorce only for some great misconduct, ‘some unclean thing’ […]. In favor of the translation, adopted by Köhler, Keil, Henderson, ‘I hate divorce’, may be urged, that the form may be considered as a participle, that the first person is often understood before participles, that, ‘saith Jehovah, God of Israel’, which follows in the Hebrew, implies that Jehovah is speaking directly in his own person.”
Taking into an account all the data presented above, I see that the more probable conclusion is that the hater is God himself.
Remember that we may infer the 3rd person singular (‘he hates’) from the Masoretes’ way of understanding the text. Differently, it could be correct to suppose the original text had the first person singular (I hate)? Yes, this is not a wild guess, necessarily. In fact, an illuminating note in the NET Bible states (bold is mine): “The verb שָׂנֵא (sane’) appears to be a third person form, ‘he hates’, which makes little sense in the context, unless one emends the following word to a third person verb as well. Then one might translate, ‘he [who] hates [his wife] [and] divorces her… is guilty of violence’. A similar translation is advocated by M. A. Shields, Syncretism and Divorce in Malachi 2, 10-16 [ZAW 111 (1999): 81-85]. However, it is possible that the first person pronoun אָנֹכִי (anokhi, ‘I’) has accidentally dropped from the text after כִּי (ki). If one restores the pronoun, the form שָׂנֵא can be taken as a participle and the text translated, ‘for I hate’ (so NAB, NASB, NRSV, NLT).”
(Calvin supposed, instead, a switch from verbal form [‘to divorce’] to a substantivized participle [‘divorcer’], “’For he hates the divorcer, (or him who puts away,) Saith Jehovah, the God of Israel; And the coverer of outrage on his own garment, Saith Jehovah of hosts.‘”)
Second (and last) Difficulty: “The ‘violence’ of the passage is linked with the previous argument (breaking the marriage covenant) or it is linked with other kind of violent deeds?
I allow to respond an ancient – and often keen - commentator (John Peter Lange) (bold is mine): “[…] ‘And him who covers with violence his garment’. The design of this clause, parallel to and coordinate with, ‘I hate divorce’, is to express more emphatically the consequences and enormity of the sin, that it is exceedingly heinous, and the height of cruelty. We read in Psa 109:18; Psa 109:29, of being clothed with cursing as with a garment, of being clothed with shame. We find the same construction of כִּסָּה with עַל in Num 16:33; Psa 106:15; Hab 2:14, where the object covered is preceded by עַל as here. ‘The earth covered them’, ‘And covered the company of Abiram’, ‘As the waters cover the sea’. We therefore understand the relative, which is frequently omitted, and regard this clause as the continuation of the preceding, ‘I hate divorce’, only with a more emphatic statement.”
Also the Cambridge Bible presents an alike concept (bold is mine): “‘For one covereth … his garment’. Rather, and ‘him that covereth his garment with violence (R.V.) (do I hate), saith the Lord of hosts’. Two things, in relation to the subject in hand, Almighty God declares that He hates. He hates ‘putting away’, for it is a violation of His primæval law, ‘What God hath joined together, let not man put asunder’. And He hates ill-treatment by the husband of his wife, which stains and pollutes, as it were, the garment of protection which he is bound to spread over her. By ‘his garment’ many commentators understand ‘his wife’. But no such Hebrew use of the word has been adduced, and the Arabic use which is alleged is not conclusive.”
And, the ESV Study Bible along the same lines (bold is mine): “The expression covers his garment with violence is probably a figure of speech referring to the defiling of one’s character with violent wrongdoing (see the similar image in Ps. 73:6; 109:18; Rev 3:4; and see the opposite in Job 29:14; Ps. 132:9; Isaiah 59:17; 61:10. […] as Malachi stresses, […] divorce based merely on the loss of affection breaks the marriage covenant and defiles one’s character, since it is untrue to the creation ideal of faithfulness (Gen 2:24 […]).”
I hope these notes will be useful for you.