Move on, it is hard but you have to. You say you split five years ago but he keeps coming back. Plus he has a new girlfriend who is pregnant, this is not fair on either of you. (You and the other lady)Does she know he's still in love with you? She is pregnant and doesn't need this sort of thing pregnancy is hard enough. I just think that both of you ladies should walk away from this man then he will see what he has lost. You are worth more than that.

I believe forgiveness is only for people who deserve it. He is unfortunately not only playing with your mind but your heart as well. What about your children is this a good example? Would it be OK if someone did this to your children? He may love you but in a sick twisted way can you live like that? My ex left me and once his feelings turned someone else I couldn,t let it go I felt betrayed. It,s too hard to trust someone after they betray you,no way would I let myself be used sweetie. You deserve a better life and so do your kids. You deserve someone who will love for yourself and respect you by being in a monogamous relationship as well. He needs to grow up and get his life together for your children but if the fruit of the tree is gone it,s time to move on. Take some deep breaths remind yourself you are a special person and deserve only the best and that,s what you will get. The other woman deserves his lying cheating crap not you.

Nope!...He lost out on 'That Loving Feeling', when he left the first time. He just wants to run away from responsiblity. He's insecure with himself, and you are a 'Solid Rock', that he climbs up onto, when he gets lost in the forest. He has to learn to become the 'Rok' on his own. If he has been with this other women for 3 years, verses 3 months, (not that this makes a difference), and he never told you about the new baby or her, then ask yourself 'What's wrong with this picture!?'
Yaaah!...He's started a new family!...and who knows how many other family's.
If he was on his own, trying to do the right things to prove he was 'The Man', for you, then sure, take a chance, work it out.
But, he didn't do that. He got another woman pregnant. That's a BIG NO-NO! If he did that once, he'll probably do it again. He won't tell her anything, cause he doesn't plan on leaving her. At least for now, anyway. I have seen it all before. It never ends on a happy note.
Move on, become independant and strong. Say "NO"!...It's hard, but, if you don't your kids will do the same things, the two of you are doing. If you stand up for your self respect, and self esteem, get 'Prettied UP!' and have a back yard party, and invite a friend, maybe even invite, the EX and his Girl-Gone-Pregno, That should spice things up. Show nothing but love and concern. That's sure to tilt the Trees and spill over the Rim of Gin. Do it with a SMILE.
You don't need him to work it out for the family, he already messed up their heads. He can still be a dad, he can take them over his place for a change. Don't lie to your kids, and cover up for him. He has to be a man, and do the right things or leave you alone.
Move on! But do it with LOVE.
Respect yourself.

A few years ago a dear friend said to me. "If you are going to get involved with her again (same situation, genders reversed), this time, please, DON'T GROVEL! Ouch! It's not about him- maybe he's BS-ing, maybe he's sincere but sick and honestly can't help himself- it's about you. What will your children learn by observing what you do?

This is a prime example of an ucommitted and immature person so if you are willing to continue to "raise" him as a wayward child then welcome him with forgiveness in your heart and assurance in your mind that he WILL NOT change.
In your situation I would change the locks and and head to court.

I agree with most of the replies so far.. He's comfy with you because you are TOWING THE LINE.. he's obviously starting a new life with a new person. Tell him to go to his new family.. it's most likely his guilt that keeps bringing him back to you anyway.
Move on without him and find your happiness.
Many Hugs to you.

I was in a relationship for 15 years and had two kids, only to be cheated on and feel like a big piece of crap all the time. Now, 5 years later, I have moved on and I realized that life is TOO short for that. You are a better person than that and you deserve to be treated so. You deserve 100% of the love and attention. With him having a gf and a baby on the way, you and your kids will be left with 10%. That's not fair to you. Move on. You will find someone who loves you to death, I did!!