Here is some of my experience.
1. I used to use legit sounding places/people that offered extra's (that wasn't crazy obvious from the ad) but was reviewed/endorsed by this site, but one time I suggested a place for the wife to see for her back that I knew was legit from this forum but gave good massages, then she went and googled the place I recommend she got all the messages about guys asking about happy endings etc. So I pretty much stop going to "RMT's" openly that gave receipts even if I didn't claim them just as proof that I went to a legit place. This forum unlike CAF is open and google can scan it and it's keep in it's search database.
2. You don't have to start off with TOFTT, go for the easy scores first. I missed a few great provers Sunny, Ava, Miss V, when they were actively advertising for customers. I ended up see other providers as I was trying to figure out hidden messages with in their ad if they do extra's etc. Quite a few were a bust and only later on saw Miss V once in Calgary and Sunny a few times.
3. You can buy a second hand phone off kijiji and then buy a sim card from amazon, you can even just use the phone with no sim and just wi-fi and use a only data like the other guys describe. For us, a charge for $30 on a CC bill doesn't create any scrutiny, but not sure how eagle eye you guys are with budget/money. I only used a burner in Mexico, but most providers here don't solicit and if they do it's generally reported here. Amy and a few others do that kinda of shit and they will get a block number ASAP. Unless you have both use icloud, I use aliases for provers in my contacts and I delete conversations when done. IF your wife look at a list of numbers you texted and calls then to confirm who they are and have a relationship what she accounts for every second you not in the house or at work and you need a receipt for every penny spent you might want to think about what life you have left and maybe move in a different path. I don't know your whole story but from the few sentences you proved...
4. The reason for this hobby is different for everyone, for myself it was purely accidental at first, but it was quite a first WOW factor that I decided to keep going. Our sex life though the ages with pregancy, kids, work stress has been up and down but never out, so it was never a replacement for intimacy, but for me, just an added layer of different experiences that I wouldn't get with my partner. With one provider I regularly have a multi-organism lasting 5-10min of one wave after another without me actually climaxing (that same provider that was my first HE). This is me getting 100% attention to my body though a relaxing massage with a build up of sexual teasing to a massive full body heighted awareness. Just the other day I got my first full on prostate massage release. I have in the past have providers play with the back door, but this one was full on three knuckle deep. It was good... but I'm up north on business and the sticker shock of how much she asked for just the massage then the HE on top of that was the cost of a mirco in Edmonton! But since covid has kept every one at home, my times out to see a providers has been drastically reduced so I ended up going through with it. She did back walking what was a first too for me and then at the end she sat on the table with my legs warped around her and when she was doing her extra stuff she was playing with the butt a bit and at that point I tilted my pelvis to let her have more access when that happened and she saw I liked it and asked is I wanted a PM and I went forth. During the initial txt's she was very short and vague and didn't say anything about extra's (just like what you worry about), but once I was in her condo, she was instantly asking if I want extra's on top of the already expensive base rate for her massage! She did ask if I wanted full service and now that I saw her I'll txt her to see what that cost is and haggle a bit more over that phone about the price and what is included now that it's established on what she provides.
5. Risk is always relative to the reward. The reason to keep it to providers is that it can be scaled, looking for a side piece like a mistress/girlfriend/suger baby is the time commitment for a relationship and that chance to get caught when you are constantly "working late", here I send out a txt for a time that I can get away and no one will notice and if one is not available then there is a good change some one else is. I don't form relationship or have any feeling for these people as it a purely a client-provider. Miss V was my first FS provider and I turned down her BBBJ cause I was super paranoid about STD's and I didn't know she was going to offer that when I saw her for the first and last time. Now after looking into that, the risk is very low (to me it is).