You have no reason to commit Zina for the following reasons:
1. Zina is filthy, and Islam dislikes filth. imagine lying down with someone despite having a spouse at home waiting for you to return. that’s filth…
Zina imagine telling your kids “Don’t commit zina”, but you hide and do the same act with someone else’s mother, sister or daughter. that’s filth…
1.2. Imagine opening your private part in front of someone other than your legitimate spouse. Where will you take the shame? Allah ﷻ is watching you… the angels are bearing witness, my dear.
2. Zina is dirty – people who commit zina in marriage can go beyond zina. they can commit any dirty act; bcos zina is the highest form of dirt.
2.1. Sexual intimacy with a non-mahram partner exposes you to insecurity. but you do it anyway – despite the saying of the prophet “Shyness is part of iman.” when you undress and intimate with a stranger or non-Maharam, where do you keep your shyness?
2.2. Unwanted pregnancies happen. at times people catch STDs and infect their spouses. that’s dirty. where is your sanity when you do that? How do u justify aborting an unwanted pregnancy, now from committing Zina to committing murder…astaghfirullah!
3. Zina has fitnah in it – when you commit Zina you open yourself to the following:
3.1. Poverty – scholars said, any man who is committing zina, his sustenance is going down. but if he is lucky and his sustenance goes up, it means, Allah is letting him gain a lot in Dunya, but in Akhirah, he will be the poorest of all.
3.2. Curse – when you commit Zina, you live in the curse of Allah ﷻ and his angels. and this curse not only affects you, but it affects people around you, especially friends.
3.3. Wrath of Allah ﷻ – one of the biggest sins in the eyes of Allah is zina. it is so big that Allah instructs killing [stoning] against a married person who commits it. shirk is the greatest sin, but Allah didn’t instruct killing. so imagine the sin of Zina.
4. Reward for abstaining from it – this is more reason why you should not go near Zina.
4.1. In Jannah, Allah ﷻ promises to give you everything you desire. so you can desire women or men. and they will be given to you. Allah ﷻ describes the men and women of Jannah as nothing more beautiful than them in the whole world.
4.2. Abstaining from it means you are patient. the reward of patience is this. On the day of judgement, patient people will be sheltered under the throne of Allah ﷻ while others will be under the sun and its burning.
In conclusion, if you think of Zina ever again, then remember these points:
1. Committing the acts goes against Allah ﷻ and his Prophet ﷺ – going against them is a sign of disrespect and dislove. if you truly love Allah ﷻ and his prophet then abstain from zina.
2. Zina comes with no respect and dignity. even the people of Jahiliyyah knew this. Abu Bakr says “I am proud to say that I never committed zina or drank alcohol during the jahiliyyah period.”
3. The messenger says “Do not do to others what you don’t want others to do to you.” Zina with someone’s daughter or sister or mother is an invitation to someone to commit the same act with your daughter or mother or sister.
4. If you do it and things are still ok in terms of sustenance, then you should know that Allah is setting a trap for you.
5. Last point, what if death is what comes after you committed your last zina? what if you die while doing it? what if immediately after doing it without performing ghusl, you die???
Astaghfirullah Azeem 
Dear, repent now, don’t wait and don’t think about it, just repent now before it is too late. who knows when death comes?
May Allah ﷻ save our souls from Zina. 
Ameen
JazakAllahu khair for your time.
Source: Servant of Allah