two married people having an affair

One indication would be that he's married and would like to stay married.
Leave him alone! If you're looking for an affair then go out and seek out someone who is not attached and has marital obligations.

perhaps he has a conscience

Believe it or not I have one too. I have just been unhappy for so long but I have too much to loose by leaving my husband.

Like what? What state do you live in and how long have you been married? And why does your loveless marriage have to do with seeing other married people?

what do you have to lose?

someone to look after you while you cheat on him

Being unhappy is not worth whatever it is you have to lose. You're cheating yourself out of a quality life. Why would you do that? Is your husband unhappy, too?

You are married and so is he. You are in a loveless marriage - but he may not be.
He is probably haivng second thoughts about your relationship and really does not want to lose his wife.

You need to get out of this loveless marriage and find yourself a single, available man to have a relationship with.

Sheliacat,

I wouldn't advocate anyone stay in an unhappy marriage.

Say there are children involved - what are you teaching them by staying? That it's okay to be miserable your whole life?

Do you really think you are unaffected in other ways by your unhappiness? (possible examples : bitterness, fights, blaming, depression, jealousy of happy people, health issues, lethargy, no motivation at work, don't want to think anymore)

There are other reasons I can think of for not leaving.

Just remember that everyone has different circumstances in their lives, have learnt different lessons, and want different things. Look after yourself and make a life worth living, one that you can be happy with, and proud of (it's possible). And don't lose sight of what others want or need either. And still go about making your life what you truly want it to be.