First of all, your children’s reaction is completely normal and completely understandable. Not only are they both too young to comprehend such a complicated situation, but they're also at an age when comfort comes from everything being the same. Even little schedule changes can throw them off, so changes of this magnitude are going to hit them hard. But children are resilient, as long as they are loved unconditionally and feel secure in that love (even when there isn't much else to feel secure about). So try not to worry about how this will impact their future. Instead, just focus on now (kids live in the moment, anyway).
First, let’s tackle the regression that typically pops up with divorce and toddlers (or anytime there’s a big family change in a young child's life). Don’t push toddler milestones like potty training right now, as the added pressure won’t be good for anyone in the family. Hold off for a few weeks (or even a month or two) and when you reintroduce training, do it with positive-reinforcement charts, stickers, the works. If your toddlers are acting like babies, don't call attention to that, but do make a big deal whenever they behave like "big kids." Have them "help" you more and let them know how much you appreciate their pitching in (even if it winds up creating more work for you).
As for their fits, stay reassuring, understanding, and as patient as possible. That’s not to say you should let house rules fall by the wayside or allow your guilt (and moms who divorce with young children always say they feel plenty) to justify becoming too indulgent. Children, no matter what circumstances they're facing, need and actually crave limits even as they fight them with every fiber of their little beings. Age-appropriate limits that are consistently enforced make them feel secure and grounded and help them know what to expect. When they act out, discipline as necessary but calmly — as a way of correcting behavior, not criticizing it.
More about Marriage and Relationships
To help put them at ease, make a real effort to find the time (even though that’s really tough between the divorce and the toddlers) to stop and hug your honeys, sing them a song, and tell them you love them so much. Reassure them that Daddy feels the same way, even though you don't live with him anymore. If your critters see you crying once in a while, explain, "Mommy felt sad," and then quickly hug them and say, "But hugging you makes me happy!" so they know it wasn’t their fault that you were upset.
Read to them, too. Look for picture books that talk about parents who don't live together. Let them know it's okay to be angry and sad. Encourage (very basic) role-playing for your older child, so he can work out his feelings. Also, provide lots of safe physical outlets, like a pillow to punch or a stress ball to squeeze. (A quick Mom demonstration might even make your wee ones giggle.) Most importantly, stick to every single routine you possibly can and ask their dad and other caregivers to stick closely to those routines too. The little guys need to know that even as some things change, lots of things will stay the same. Don't have that many routines? Start some. If you’re splitting custody with your ex, establish a "going away" routine and a "coming home" routine, special activities that they’ll come to associate with going and coming home (doing a family dance, for instance, or eating pizza).
And remember: Kids have keen mood radars and what they're picking up on is your stress level, which is understandably high. They may also sense the tension between you and their dad, and that's unsettling to them too. Both of you should make a concerted effort to avoid talking about the other in disparaging ways. Even if you think your children don't understand what you're saying, they can pick up signals from your face, demeanor, and voice.
Sending you hugs to help you through this hard time,