It's not that easy.
I can't just choose not to believe.
Then don't stop believing.
It comes down to you being willing to accept the teachings of the church or not. If not, you need to find another church that fits what is actually in your heart. If you truly do believe the Catholic dogma around marriages then you are going to have to accept that you are not going to ever have a girlfriend. Accept what you cannot change and change what you cannot accept.
What do you actually believe?
I am 55 years old and could easily live another 30 years.
Do I live alone for 30 years and maybe go to heaven?
Do I try to get a girlfriend and a wife and end up in hell?
Again, what is in your heart.
If you truly believe such will send you to hell then I would hope you would be willing to make such a sacrifice - eternity is a long damn time Blackrock. However, if it is just a matter of complying with Church dogma, that is a different story. I would say, not to be to forward, that you need to do some real soul searching to discover if it is the Catholic faith that you truly believe or if it is God you believe in and follow church doctrine because it is the one you belong to.
I have no doubt that your religious leaders will help you through this if your heart is sincere and you truly do believe in the Catholic faith. If you try and comport with dogma that you really do not truly believe in though it will cause rot and resentment. That is not what faith should bring.
I ask again, do you know what you truly believe? And I do not mean what you think you believe or what you have followed thus far. It is very, very tough to truly look within yourself and discover what you truly have faith in, where your heart and soul really is.