Stop smoking and drinking, exercise, get lots of rest, take mega-loads of vitamins, take herbal suppliments (Elderberry tablets, Echinesea, Garlic, St. John's Wart, etc), eat healthy and reduce stress somehow.
One of your warts should be biopsied so you can confirm your strain. Do not assume it is just the low risk strain until you know for sure.
Your last question is impossible to answer. If you go with the assumption that condoms are 70% effective, then its 30%. But it also depends on how safe one plays. For example: use of dental dams by your partner for oral sex on you, wrapping a dental dam around the base of your penis, wearing a shirt and boxers or pants, wearing socks, identifying up front which hand you use to touch yourself vs the hand that you use to foreplay your partner, keep kissing to the minimal, not performing oral sex on your partner, etc. As I understand it, this is a skin disease and whatever can be done to reduce skin to skin contact reduces the odds of transmission to your partner. Obviously, very few people will do as I wrote here and so it is no wonder that 6 million new cases are reported each year.
And here's the final rub: Go to a STD dating site like I did recently. Despite the millions who have it, the % of people on that site with just HPV is like 5% with the rest having Herpes or HIV. Why? Because some people don't know they have it, people claim to have it cured when the warts disappear for 6 months or more and are dating non-infected people which is what you are trying to do. Really, the ideal situation is for people with a particular strain to date someone with the same strain. That would make life simpler, yes?
Condoms lower the risk to about 70-80%, and having protected sex whilst warts are not present lowers the risk even more. It's never 100% and it sounds like you have to be extra careful due to your outbreaks being so frequent. Generally people who have conditions which weaken the immune system have trouble with genital warts, however there are an unlucky few who experience them badly when they are infact perfectly healthy. You seem to be doing the right thing so far, just keep at it and strengthen your immune system as much as possible.