Just want to give you your props, mamasiobhan, I have been there, done that, and got the t-shirt. I found out when I was 6 months pregnant with my fifth baby that my Insignificant Other of 11 years not only cheated on me, but had an entire FAMILY on the side, with a six month old baby. The baby was born the day after his birthday, while we were at a hotel sleeping off our little celebratory tete a tete (and making that 5th baby). And the woman he was with was not quite the "settling down" sort, if you know what I mean. Turned out that 1 of those kids wasn't even his, and she doesn't know who out of 3 other men is the father. Nice, huh?
I been through the whole wait and see with regards to testing, it stinks.
I tried to work it out for a couple more years, and we even had another baby together, but it didn't work. I know where you're at, though.
I had an insatiable need for sex with him after I found out, too. I don't know if I was trying to prove I was "better" than her, or if I wanted to make her jealous because I still had him, or if I was trying to wear him out so he didn;t have energy for anyone else, or if I wanted to feel the same way I used to feel before I found out about it.
Even though I am now married to a really great guy, I still love the S.O.B.