Will there be sexual relations in heaven? Some say "No" because Jesus says in Matthew 22:30 that we will be like the angels. But, in the context of what Jesus was talking about in Matthew 22:30, what Jesus meant is that we will be like the angels in that there will be no marriage in heaven.
A question was given to Jesus concerning a woman who had several husbands in her lifetime (each husband having died and the woman outliving them all). The question given to Jesus was who will be the woman's husband at the resurrection since she had several husbands. Jesus responded by saying that, like the angels, there won't be marriage in heaven. That doesn't mean there won't be sexual relationships in heaven. Marriage is required for sex only in this life. Heaven is another issue.
We won't be like angels in every other way. For example, Scripture says that believers (Christians) in their next life, in their resurrected (immortal bodies), will enjoy food and drink, even though eating and drinking won't be necessary anymore, but believers in glory will still be able to enjoy those and other pleasures. After His resurrection, Jesus Himself ate and drank with the disciples. Jesus said that in the future Kingdom He would enjoy wine with His disciples again. Angels, on the other hand, are strictly spirit beings and don't consume food or drink.
How can God allow sexual relations in heaven without marriage? In heaven there's no need for anyone to belong exclusively or permanently to another because there will be no building of families as marriage involves. Scripture teaches that marriage is a unique test and picture of faithfulness, but in heaven no such test is necessary for only the faithful will be there.
There is no logical reason for why there won't be sex in heaven. If other bodily enjoyments like eating and drinking will be there then, most certainly, it is reasonable to expect that there will be sexual enjoyment also. Sex in heaven will be driven spiritually and by perfect love.
Human sexuality is so powerful because it is not only for reproduction. It involves intercourse of spirit and soul, as well as body. The Song of Solomon in the Bible is filled with sexual imagery. Human sexuality has meaning beyond marriage and having children. Seniors have sex beyond childbearing years! Animals only have sex during mating season and only for reproductive purposes. Animals don't have sex all the time, but humans do.
The Bible teaches that there will be both spiritual and bodily enjoyment in heaven. Psalm 16:11 tells us that in God's presence there will be fullness of joy (this is spiritual) and at His right hand there will be pleasures (plural) forevermore (pleasure is something experienced physically). In fact, various passages in Scripture imply that for believers all human faculties (spirit, mind, and body) will be actively engaged and fulfilled throughout eternity. Eternity won't be boring!
There are some good books and articles on sexuality and heaven written by Christian scholars.
Because Jesus Christ, God's eternal and only begotten Son, paid the penalty for sin, on our behalf, that we can never fully pay, and rose from the dead, the Bible says that through genuine faith in Christ we can be forgiven of our sins and perfectly enjoy God's presence and everything He has for us in heaven. The Bible says, "For God so loved the world that He gave His only begotten Son, that whosoever believeth in Him should not perish, but have everlasting life" (John 3:16, KJV).
Just as a co-signer to a loan takes the responsibility to pay someone's else's debt should the loan go into default so too Christ took the legal and moral responsibility of paying the debt for mankind's sins. Because Jesus Christ paid the penalty for our sins, God can be just in forgiving us our sins when we put our trust in Christ as Lord and Savior.
Love and follow God first, and some day everything and all enjoyment, physical as well as spiritual, will be yours for eternity, my friend. "No good thing will (God) withhold from them that walk uprightly" (Psalm 84:11).