– where does it come from?

It's normal to believe that love is something which comes from the outside. Something we need to be given by others. However, this is not the case. And thank God for that, because it means that we are in control of love. We decide ourselves how much love we are given in our lives. "You cannot means that Susana?!" Yes, I do. It's not your partner, friends, family, children or others who are responsible for that you have love in your life. It's yours. Love comes from inside. Inside you.

We often seek love from others. Especially our partner. However, if you do not love yourself you cannot love another person. I know it feels like you love your partner, and you do. But really love someone for who they are, that you can only do when you love yourself first.
You are the only person who you have to live with for the rest of your life. Who else you have in your life is your choice. 

Not everybody is heterosexual. It can be a challenge to have a different sexual orientation as there are still mostly heterosexual people in the world.

It can be difficult to be different from most people. So, it's a question of being ok with oneself, just as you are.

Other sexual orientations can be homosexual or bisexual.
Transsexual and transvestite is not related to sexual orientation.