Good for you speaking about this to your wife. Some wives accept the bargain, meanwhile others, like my wife, won't even talk about it. Nada. Bury their heads in the sand. So frustrating, but one has to live their own life...so you just act, and shut your mouth. You will feel guilty for months, but then that goes away. Trust me, it does--and I am a guilty type of guy. Your marriage, surprisingly, will get better, and then the affairs will become part of your life. I won't lie, it is a bit of a juggling act, and you need to lie (or white lie) now and again. I am ok with it, as my life is really rich now. I have my home life at least 5-6 days a week (and my relationship with my wife is civil and the kids are well looked after), but I have something to look forward to once a week. I also try to take a trip or two a year for weekend with the mistress. These are amazing--I do them around work travel to avoid detection.
To answer the safety question--and it is a good one-- go for divorcees with small kids (5-15). They have been there, done that. If the kids are too young, there is always babysitting issues etc.... Remember, these ladies got divorced for a reason, and their kids are #1 in their lives. But they are not nuns, and many have hyper, but unfulfilled sex drives. This keeps you safe and active; and the ex is usually not around, or nutso, as they have moved on too.
For 18 years of marriage I received zero (literally) oral sex. now I get it it whenever I want, with ladies who into it. I have never paid for sex once. Although going for dinner and drinks is part of the equation. Also I have noticed women over 40 are extraordinarily good in bed after a divorce. No joke. Way less reserved.
Sure, some ladies will want more than a long term, ritualistic weekly fling (and maybe that is where things need to go)...but be clear with them at all times. Be precise about your needs and wants. Don't talk about your wife much, but make it clear she is part of your life at times, and that you will not leave your wife until the kids are gone (or whatever). You will be surprise how many women will be receptive. Again, I have had 5 affairs in 7 years--all really good. One for a long time--and it is still great. Two more casual affairs, where I have sex maybe 5 times a year with these ladies....Only one was a bit nutso, and she was single (not a divorcee).
So stay with the ladies who have been there, done that.