Boyfriend has gone on anti-depressants. Not sure how to feel.?

I've been with him over a year now and he has had some issues in his life that do get him down and they are things out of his control. My brother suffers from depression and I've spoke to my boyfriend about it for comfort but he always dismissed it saying depression isn't a real illness and that it's attention seeking.

Today I took him to a doctors appointment. He never told me he booked one. He never told me what for. After it he got his prescription which turned out to be anti depressants. I asked him why he never discussed his feelings with me and this made me sad. He said because I cant change anything. It hurts me to know he used to say it wasn't real and now he's on pills for it but never spoke to me about it. He doesn't see why that hurts me.

The ones he is taking are fluoextine which apparently are for major depression disorder. He told me they were for minor depression and he can stop them whenever. But that's not what my research is saying. They can make things worse and can decrease his libido, cause erectile dysfunction and lack of wanting sex. Apparently they also change peoples perception of love.

I'm scared they are going to change him and change his opinion of me. Im scared they might decrease his sexual desires, find me less attractive and our sex life will go down hill. I feel that this is going to effect me and effect us and I'm not sure what to do or how to feel.

Any advice?