Aww, undecided I know where you're coming from on so many of these questions!!
Yes, I get that 'twinge' of insecurity/jealousy every once in a while when he is going to be with someone younger, thinner, firmer but then I stop and remember that maybe last week I was with a 6'4, 29yr old hunk.
That sort of puts everything into a better perspective for me.
I am 53, hubby is almost 56 so younger, firmer, thinner are all on my list of minor insecurities while taller, built, younger and a full head of hair are on hubbies list.
I was raised in a Roman Catholic family, even went to all Catholic schools! I didn't date until almost 3 yrs after I graduated from high school! I wasn't a virgin when I married at 22 but I wasn't what one would call very experienced either.
As far as worrying if he will run off or be pulled away by a single woman, in all honesty I have found more unhappy married women who I personally could see as a threat in this lifestyle(open marriage). I have to try to explain this better; Neither of us are seeking to replace our mates, but there are many women & men in marriages who are staying put in an unhappy marriage-just waiting until someone better comes along.
Those 'predators' are the ones who concern us and who we watch for with a sharp eye.
We have seen marriages be ruined due to infidelity in the 'vanilla/non swinger' world and we've seen it happen with both-a married lover & a single lover. There seems to be no real pattern for it, IMO. If a person wants out of the marriage, being with singles won't be the sole reason or draw to cheat. Cheating can & does happen both while swinging or being in an open marriage.
STD's, yes they are out there and yes they are a very real threat. I have worked in hospitals since 1970 so I have been around disease and the information for what seems like forever. I do get tested, use condoms and ask a lot of questions of my potential partners. Hubby does the same.
I run as much if not more risk working in a hospital as I do by having select lovers who I know are fully tested.
Also, think about something else which helped ease my mind, I know we are both engaging in sex with others and we can discuss the safety issues openly. If either of us was cheating then our spouse wouldn't know they were being put at risk and in my mind that is much harder to accept.
Ok, onto the religious issues. That is one you will have to search in your heart and mind. Ask yourself a few questions about the recordings in the Bible. Remember, in the Old Testament, it wasn't abnormal for men to have more than one woman and in fact many acts we now think of as illegal were tolerated and even encouraged-young virgins being given to males, etc.
So for me the Bible and religion are good guides but not the end all authority for my actions. I follow a code of ethics which includes these words "If it harms none, do as ye will", and I do follow that by not playing with marrieds/attached folks who are not in open relationships, I won't help someone cheat on their spouse. I am always respectful of the other persons marriage and their right to their own desires. Ok, I'm getting off on a tangent here!
I do have a site that is for Christian swingers. I will have to find it and I will post it for you. I don't know if it might help but it's a place to discuss the spiritual side of your choices with others who have wrestled with the same concerns.
If there's anything I can answer or help you with post it here or pm me.
Just take it slow, ask a lot of questions and you will be just fine no matter what decision you eventually make.
Kathy