OP:
Just be sure it's for the right reasons. I'm certainly not equipped or educated to deal with these things, but it seems to me that your conviction isn't really as strong as you'd like it to be.
You like kids in general and you already have what some would call a substitute (pets).
The majority if your original post dwells on the emotional stress associated with subsequently losing your children due to divorce or similar.
In summary, to me it seems like you're not really against having kids, you're mainly afraid of getting attached to them only to lose them to some other man after the wife has moved on.
To me this seems like insecurity in general, and attachment issues specifically.
While it's a valid point it just doesn't seem healthy to deny oneself something on the grounds of being afraid to lose it. Taking that to the extreme would result in you denying yourself to be together with a woman, forming friendships or being with your family, because at the end of it all, you will loose them all.
If you think about it, life is all about holding something *for a time*. Nothing is everlasting, nothing you have will ever stay. You can't buy a cat or dog without expecting to lose it at some point, nor can you have a child without expecting to lose him or her at some point, in one way or another.
I guess what it boils down to is how you view life. Rather than being afraid of what might, or will, come to pass maybe you should focus on the *now* of it all, and cherish the memories it will give you.
Of course, you can also just dismiss it all and try to rationalize your thoughts, maybe even ending up thinking like Socrates to whom having children was merely an attempt to stay immortal meant for those who were unable to foster immortal ideas.
(Socrates in the Symposium, speaking of Diotima's ladder of love -- Granted, it's not exactly what he says, but it's not far off)
I'm not arguing for or against having kids, I'm very much undecided myself, but as with every other substantial decision in life, you should be damned sure that the decision you make are for the right reasons.