First please allow me to say that becoming involved in the swinging lifestyle seeking something that a spouse isn't capable of giving, will not give or thinks he/she cannot give is risky and is swinging for ALL the wrong reasons. You both need to communicate and understand this. This alone is a basis for halting your swinging activities. Try to make him understand that you do not feel a need to be "taken care of" that the pressure to perform is becoming overwhelming for you. Communicate together on techniques that can be learned to enhance your intimacy together. There are many solutions leading to sexual pleasure in dealing with health issues. Seek those solutions together and help him to gain his self esteem back. Swinging is the very last thing that your relationship needs at this point. Allow him to see this forum, hopefully it will assist in helping him to understand your feelings.
Many swinging couples start out in the club scene. This allows you the opportunity to look without being involved, in most instances anyway.
Are you ready for your first threesome? As a couple be honest with yourselves as well as each other. Be clear as to what you expect to happen as well as where to draw the line. Be sure your added parter is aware of your guidelines and you of theirs. Relax, take a deep breath and allow the swinging encounter to happen naturally.
Long before the situation cums (Pun intended lol) you should have discussed where to make your deposit! If you find yourself in the situation and you are about to erupt, the ONLY proper thing to do is to pull out and let it flow into your hand or on the sheets. I have been in situations where the guy has asked me at that point and because we have no issues with it, it was not a problem but if issues are present it could spoil the experience. I advise you to "cover your bases" and always know where to make that "deposit" before entering the "bank"