I have a similar problem. I tried Cialis and, frankly, despite the fact that the condom means a massive erection, it did not help me in this. I think that this is a bit of a mind over the problem of matter.
Concerning the side effects of Kamagra we have to say that Kamagra oral jelly is much softer. Except for a slight heat sensation on the face there is no othe side effects for me. In the case of Viagra / Kamagra from Kamjelly.com the side effects are somewhat more severe: facial redness, increased blinking. Headaches and real visual disturbances do not occur with all four preparations but I seem to tolerate the things generally well.