The problem here, my friend, is what trying to make sex "better" means to you. It can mean for example
1. a longer act of intercourse
2. more intense orgasm
3. less anxiety and thereby more emotional enjoyment
4. more enjoyable for one's partner
5. maintaining one's erection
Marijuana, no matter the strain, only really helps #3, because the drug's mechanism doesn't affect the others without lacing it with some kind of pharmaceutical (not recommended).
It's possible the health problem you have (the one you smoke the weed for in the first place) is what's holding you back. Treat THAT problem first.