Sex life at home is nonexistent so I've contemplated seeking outside assistance for a long time.  Not sure there are any answers that anyone can give me but i am having trouble with a couple of things.  First, the guilt of cheating.  Second, the fear of STDs.  How did everyone get comfortable with these issues to finally dive in to the hobby?I know in the end it's just something I have to figure out for myself but I'd love to hear how others dealt with it.  

Everyone is different, so I’ll leave it at that. Using condoms cuts the risk of std’s.

That's Your Mileage May Vary and in this instance, it means everyone is different in how they deal with these issues.Some guys feel no guilt while indulging in p4p and others, myself included, keep out of p4p while engaged in a committed relationship.

You clearly state that the issue is sex and not intimacy, romance, or other issues. You might consider starting with a massage with a happy ending (HE; aka hand job HJ). That can provide relief in the form of release and a limited amount of intimacy. (Although the extent of the massagee - masseuse interaction is highly variable.)  If you go MP - HE but are overwrought with guilt and can't even handle the MP - HE experience you should step away for a while and try again later (or maybe never try again).  
.
There have been a couple of posts recently about making an arrangement with a GFE FS provider but not wanting to go all the way. That is also an option. More intimate that a MP but you only go as far as you want to go (as long as it is within and not beyond her limits).  
.
The guilt issue might be better dealt with with a psychologist or counselor.  

For me, the only fear I had starting out was getting ripped off or locked up. So P411 and TER were the answer for me in minimizing the risks. Now, I'm loving this lifestyle and really have no concerns, other than getting lazy and not doing my research. Which when you think about isn't that much of a issue.

As long as you maintain your commitments at home to support and spend time with your spouse and children, then how does seeing an escort for an hour a week interfere with that?   Combine that with the fact that your wife isn't keeping to her commitments, then why occasional sex with another is such a big no-no is beyond me.

My wife declines any form of intimacy: touching, cuddling, kissing & especially sex.   No matter what she says, it's not going to happen.   If she was willing to uphold her commitment then so would I.  So I do what I want.  Zero guilt.      

I agree that everyone is different or YMMV. I love my SO and I have no guilt about seeing providers and I don't have a problem with my wife not fucking like others who post here.

Try to view p4p as just two adults having some consensual adult fun together. It's not an affair. You're not giving your heart to these providers (right?).  

play games with your mind re. commitment.

I've tried FBSM a few times and enjoyed it.  I do get a little guilt right after but it doesn't really last because FBSM seems fairly harmless and low-risk.  

You went from "contemplated seeking outside assistance" to getting outside assistance really fast!  
.
The rest of the advice, above, also seemed pretty good. Don't throw away or abandon what you already have, just add something, 1-2 hours per month, to it.

The other day I went to the store and bought some invisible tape.

I made an appointment with a hot lady that has a great history of very positive reviews.  
I think I am going to start slow.....massage and maybe CBJ - just to get my feet wet (well, not my feet).  If that goes well, then maybe I'll book another appointment and go further.  I just hope that the lady doesn't mind a non-fs session.

Feel free to come back and let us know how it went.

Surprisingly, many couples find seeing a provider together puts a lot of the spice back in the relationship. It can be a little nerve racking at first to think about but if you find the right woman who specializes in working with couples, who is respectful of boundaries and open to hearing your thoughts and limitations, it can be quite an amazing and rewarding experience for the both of you. If you think she is possibly open to the idea you should look into it together. That way you don't have to feel guilty about cheating and instead possibly open a whole new window to your sex life! Something to think about Good luck to you!

I went through with my appointment.  The provider was as hot as her photos suggested, so I was pleased by that.  A CBJ is as far as I went.  I was tempted to do more, but I have this major fear of catching something that really stops me from fully enjoying the moment.  I just worry that if I got an STD, that would be the surest way of getting caught by the wife, and that would be the end of the marriage.   How do you married guys deal with the STD risk?  Am I making too much of a big deal out of it?

My wife and I don’t have sex or even kiss anymore. So other than covered FS which is really a must for everyone, I don’t worry too much about kissing and BBBJ.  

I can't speak for others, and I don't have all of your considerations, but for starters: only do what you are comfortable with and nothing more. (That goes for your hostesses, too.) If you are comfortable with CBJ, there is no man-code or machismo pride about going for BBBJ.   BTW, are you able to get tested w/o the SO finding out? Will your doctor keep his mouth shut of blab it to the SO?  Maybe you can go to an anonymous clinic?  
.
Now then, first: PROTECTION helps to PREVENT getting in trouble after the fact.  Protection can be pre-meeting porn-star quality blood tests but that I think that is very rare in this activity. How do you verify that a test is real and not faked? Or that the name of the person on the test is the person you are meeting?  Because of latency, a 3-day old negative (safe) test, doesn't say anything about what happened during the intervening period.  
.
Material barriers provide a fairly reliable degree of protection: regular condoms, FC, dental dam, .... .  Some participants go by statistics and assessments of the CDC (Centers for Disease Control).  There is a certain comfort level with BBBJ and the likelihood of any sort of disease transmission from F to M. (I forget the reverse: BBBJ M to F.) There is widespread acceptance that BBFS is a MUCH riskier activity for everyone.  And BB anal is the riskiest of all.  
.
Nancy Reagan's "Just Say No" policy introduces an even more reliable barrier to infection.  If you keep your penis several feet away from your hostess, it greatly reduces the possibility of any sort of infection.  But keep in mind that infectious fluids can still be transmitted by other materials: shared bed or bath linens, shared toys, shared toothbrush, etc..  
.
It's partially common sense, partially the science of transmission, and partially horniness that determines what each of us seeks when BCD.  
.
To repeat myself, stay with what you are comfortable with. If you are in a situation where your concerns are heightened ("Ehhhh, your tattoo scabs seem to be bleeding." "I don't have any tattoos. Uh oh!") dial it back and maybe even stick it back in your pants and get out of there. If you stay with reputable, well reviewed Providers, you should be OK and happy no matter what you decide to do.  

For the first question you need to separate the idea of sex and love. In our society we often intermingle them which causes for unnecessary angst. Sex is a physical need and desire. You of course can love someone you are having sex with, but you can very easily have sex with someone you do not love. You have a physical need for sex like you do for food and water. You can very much love someone that you take out to lunch, but also can have an awesome lunch with someone you just met.  
I have been in this business for awhile and have never caught anything. Has anyone? Yes, I am sure it has happened, but in general the risk is low as long as you are using a condom. I also shower after every client and make sure my "lady parts" are clean. I think it is just kind of common sense: if your lady of the night looks clean and smells clean, you should be fine.