After being with my partner for almost seven years. He just had a baby with another girl. We have three kids of our own. We are happy as a little family but him and I are not. I try and work it out but after this situation with this new baby I don't know what to do. Some advice please.

Leave!
(How does that advice make you feel?)

Confused... why did you suggest that?

YOU try and work it out? And what is HE doing to improve his family life with you other than having a baby with some other woman?

Wow! Obviously he was messing around... you say that the 2 of you are not happy together... then you say that YOU want to fix the relationship. Why bother? Why is it all up to you?

I have no idea why you would even stick around in this situation.

Because of the kids

because of the kids
And HOW is this helping the kids?

In the long run, this kind of situation does not help the kids. For one thing, it shows them that it is OK to accept this kind of behavior.

And HOW is this helping the kids?

They have a good relationship with him and they are happy when all of us are together

they have a good relationship with him and they are happy when all of us are together
And how often are you together now that he has a new family to be with?

And how often are you together now that he has a new family to be with?

Four to five days out the week

four to five days out the week
And how do you explain Daddy's absence the other days?

The truth... he goes to his mom house out of town and that's where they meet and see the baby.

The truth....he goes to his mom house out of town and thats where they meet and see the baby.
Again, how do you explain all this to your children?