For people who believe Genesis chapter 6 refers to Angels (sons of God) marrying daughters of men (therefore people) there is no confusion there.
Genesis 6:1 And it came to pass, when men began to multiply on the face of the earth, and daughters were born unto them,
2 That the sons of God saw the daughters of men that they were fair; and they took them wives of all which they chose.
3 And the Lord said, My spirit shall not always strive with man, for that he also is flesh: yet his days shall be an hundred and twenty years.
4 There were giants in the earth in those days; and also after that, when the sons of God came in unto the daughters of men, and they bare children to them, the same became mighty men which were of old, men of renown.
Genesis 28:12 And he [Jacob] dreamed, and behold a ladder set up on the earth, and the top of it reached to heaven: and behold the angels of God ascending and descending on it.
That is not the teaching Jesus quoted. Jesus said in heaven the angels do NOT marry. The passage in Genesis talks about angels coming to the earth and taking wives.
Here is the passage from Enoch wherein the teaching Jesus gave is found:
Enoch (Book of Enoch link
15:1 Then addressing me, He spoke and said: Hear, neither be afraid, O Enoch, O righteous man, and scribe of righteousness: approach here, and hear My voice. Go, say to the Watchers of heaven, who have sent thee to pray for them; You ought to pray for men, and not men for you.
15:2 Why have you forsaken your lofty and holy heaven, which endures for ever, and have lain with women; have defiled yourselves with the daughters of men; have taken to yourselves wives; have acted like the sons of the earth, and have begotten giants? (Gen. 6:2
15:3 You who are spirit-Beings, holy, and having a life that is eternal, have lusted in the blood of men; and have done as those who are flesh and blood do.
15:4 These however die and perish.
15:5 Therefore have I given to them wives, that they might cohabit with them; that sons might be born of them, and that this might be transacted upon Earth.
15:6 But you from the beginning were made spiritual, living a life that is eternal, and not subject to death in all the generations of the world.
15:7 Therefore I made not wives for you, because being spiritual, your dwelling is in heaven (Matt. 22:30).
15:8 Now the giants, who have been born of spirit and of flesh, shall be called upon earth evil spirits, and on Earth shall be their habitation. Evil spirits shall proceed from their flesh, because they were created from above; from the holy Watchers was their beginning and primary foundation. Evil spirits (demons) shall they be upon Earth, and the spirits of the wicked shall they be called. The habitation of the spirits of heaven shall be in heaven; but upon Earth shall be the habitation of terrestrial spirits, who are born in earth (1 Cor. 15:40
15:9 The spirits of the giants shall be like clouds, which shall oppress, corrupt, fall, contend, and bruise upon Earth.
15:10 They shall cause lamentation. No food shall they eat; and they shall be thirsty; they shall be concealed, and those spirits (demons) shall rise up against the sons of men, and against women; for they come forth during the days of slaughter and destruction (Luke 4:33
; Matt. 8:28-34
22:30 For in the resurrection they neither marry, nor are given in marriage, but are as the angels of God in heaven
. (Enoch 15:7)