Christ tells us, scripture shows us, that the road to Hell is wide, whereas the one to Heaven is narrow and difficult to travel. Its not a far stretch to make the statement that there will be many christians and catholics in hell. A lot will be for the sins of the flesh.
It is by no means an easy life, and who said it would be? Christ didn't.
I used to be thoroughly annoyed/despairing over the amount of people who were living in horrific sin. Catholics who were contracepting, fornicating, aborting, co-habitating. I have "catholic" friends who partake in the Eucharist who are engaged in promiscious homosexual activity. It was very hard to watch.
One day, when meditating on what it meant to have "full knowledge/full consent", I realised that so many of those people living those lives just have no idea. They are so incredibly ignorant. And those who do know better, have fallen so far from the light that they can barely see their way back. I went from being angry and annoyed at those people and their actions to feeling absolute pity.
So what did I do? I started praying for them.
The secular world will make excuses, have been peddling the "sex is natural, have it when you want, with who you want, however you want, regardless of marriage". People have fallen for this, including many uneducated catholics.
As for the teaching of the Church, its God's instruction for our life. Its not a "lifestyle choice" its a requirement. If we fornicate, if we contracept, if we engage in homosexual activity, if we abort, we will condemn ourselves to Hell. Christ spoke of Hell more than anyone else, why? Because he was warning us. There is a Hell, people are going to go there, people are going to go there for sins of the flesh.
Of course, not doing x to avoid going to Hell is bad motivation. You should not do x because you love God and you know it offends him, and if you love God will you try your darnest not to hurt or offend him.
God loves us, He wants the best for us, sex out of wedlock is not in our best interest.
Look around society and what do you see? Yeah, a hard life trying to stay chaste, but look at all the messes caused by fornication. STDs, unplanned pregnancies, abortion, co-habitation, divorce rates through the roof, kids being raised in single parent homes, kids suffering from divorces, women and men gravely emotionally wounded by exes and harmful sexual experiences, increased rates of date rapes and rape, huge porn addictions that actually change the chemicals in the brain to make it difficult for a man to gain arousal from a "normal" woman, taking that damage into marriage is not helpful, masturbation, loneliness.
What more does a person need to see that the Church's teaching on sexuality is the best thing for us. It came straight from God, these teachings, they are not out of the mouths of bitter old virgin men sitting in dusty old churches wanting to spread their misery. God built our bodies, he knows how we work, what damages us.
Pray. Spend time in adoration. Pray the rosary, Mother Mary is a perpetual virgin, she knows better than anyone what its like, pray to St. Max Kolbe who accepted both virginity and matrydom.
End of the day, our modern day complaints about difficulties living the Christian way are nothing compared to what Christians have faced through the ages. No one's going to feed you to the lions for having a Bible.