I know dude, nobody wants to lose nothing but i would strongly advise in doing your research before and strongly suggest also in taking some doctors advise while doing it. I really think they know best, especially the doctor who prescribed you the ssri's. And get their advise with a grain of salt also and keep in mind that doctors are humans also and the medical system of these days is strongly bombarded by pharmaceutical companies and many other institutes that have their interests. Please do your research before taking any action, it could save you a lot of future unnecessary struggle.
And my personal opinion is that nobody can know unless they try it unfortunately but this comes with a risk that not all of us are willing to take, it all depends on the individual. And as i said, as long as you are on 2 different drugs that can cause sexual sides, it's impossible to actually know which one of them is causing it. Let's say the doctors gives you a new one, you take it and after a few months your body is fine and the sexual sides from the last drug are gone, only then i think it's "safe" to try finasteride and see if it gives you sides also, i really think it's the only way in doing it, but this is only my opinion of course, a really good and informed doctor could give you a much better advise maybe...