I've been in a relationship for 19 years she left me took our kids six months ago we tried to work it out last month she started acting strange found out she is talking to another man my heart loves hers my mind is angry how do I let her know I love her without getting angry?

I have a feeling she isn't concerned that you love her. I have a feeling you can't trust her even if she wants to try and work it out. Personally I would leave all the communication, as far as you and her, up to her. What is the point in telling her how you feel if her heart is with somebody else. You will only hurt yourself.

Anger is more productive then pain, that's what I'm learning (granted mine was not as long as a relationship/as serious one where it involved kids but If she doesn't feel that the life you two shared is valuable then why are you.. be the bigger person about it and take the high road, You cannot do anything right now and its completely up to her (again, This is what I'm doing myself so maybe it will help you too) so be cool and just deal with her as someone that is not the person you fell in love with (because lets face it if it was, this wouldn't be happening) and love your kids cause this is probably the worst on them. I say this coming from a home that never had parents stay together. Take care man

I agree with n0help... that if she's preoccupied with another guy, chances are, it's over between the two of you. What's important, though, is that although you cut her out of your life, you have to keep the kids in your life.

how do I let her know I love her without getting angry?

You don't. You get a lawyer, and get the process going to have a part in your children's lives. Make them the priority, and not her. You deal with her through the courts.