AIBU to worry about managing financially after separation with two children?

If you have savings over 16k you won’t get any UC, and maintenance is unlikely unless he agrees to it privately. The kids need to be registered at your address not his if you want UC and child benefit

You need some advice.
50/50 is the starting point for you both to walk away and start afresh on the same footing without too much disparity in the standard of the kids living.
Stop thinking about you - it's about them. Stop thinking about his/mine - they are joint marital assests. Do factor in pensions.
Men don't like (generally) to share pensions ongoing. There's usually a tiny bit of motivation there to agree to shifts now.
What value house could you both look to walk away to? Based on max mortgage and max equity each? (which will prob not be equal). It's a bit of a fiddly sum. For my ex and I it was a £250k house each - him with £50k and a mortgage and me with no mortgage. That was a 75/25 split of our assets with him keeping his pension and his businesses.
Also bear in mind that fighting in court will cost about £20k each. It's much easier for negotiating.
Really you need a clean break. If it's truly 50/50 (incl holidays and life Admin) then no maintenance and split costs of uniform, school food etc down the middle.
You only have to say the kids live with you and noone else claims to get child benefit. Don't forget your council tax will go down and your food bill.
It's daunting but you can do this.

As a social worker I would consider setting up a business.

Care businesses (mostly franchises) required someone qualified in your field to operate them and can give an opportunity for you to increase your income significantly once you are up and running.

I live on a similar amount it’s tight but doable. I am forensic about my finances eg use cashback cards and sites for insurance etc, move my small savings around for best interest, switched utilities, minimised subscriptions etc.
you do have too much in savings for UC but won’t once you buy a car and he takes 50%. You can get UC up to £50k if your dc are disabled. The calculators are fairly accurate
His higher income and mortgage capacity will be a factor and may mean a different split than 50:50. Check what mortgage capacity you have and he has on mortgage calculators. You could also look at extending the term.
If he earns much more then 60:40 split of assets may be achievable don’t assume it will be 50:50. If he is a good dad he should want you to be able to stay nearby so dc can easily go between houses and schools.

if you are 50/50 typically you don’t get maintenance but he should be paying 50/50 for childcare, all child related activities etc. if you are amicable you can come to whatever arrangement you like to a point so if he offers you x maintenance you need to decide if this is preferable to a pay 50% arrangement

UC will be affected by savings, it’s shit but you’d be better off without the savings in that sense… It’s unlikely you’ll get CM if it’s a 50:50 split for obvious reasons but the upside is you’ll only have to pay for their food 50% of the time. If he’s a decent dad as you say he will want to contribute towards clubs, uniform, school trips but most dads I hear of don’t- they think CM is adequate.

It’s scary living on a single income, and feeling responsible for keeping everything covered. The good news is you have a very stable, if stressful job.

Your take home is quite low given your income, I’m assuming there’s a student loan in the mix. In terms of spending, if your income is what you’ve calculated you should be ok. Yes things will be tighter but if you start now budgeting you’ll have a good idea of what it will look like.

When I was on one income I used the You Need a Budget app (YNAB) which helped me figure out where my money was going, and to save for annual costs eg car insurance etc. It just helped me control things more easily.

It's normal to worry about this, I did and I have a very low paid job. When ex left, I upped my days from 4 to full time.

You will be fine and will adjust.

My exH made sure I had money every month for household costs etc. and had the kids a lot at his house. I never claimed UC, I didn't know I could.

Enough to live on definitely but I would expect a drop in living standards now you don’t have access to your ex’s very high salary beyond the CM payments (if they materialise) and only until the children are 18, I believe. Would you consider a change in career?

@Therewegothen that's good to hear. In that case he may well be happy to pay some CM on a voluntary basis to help with your increased costs.

Maybe look at shared owership
UC will pay the rent element if needed
maybe you could buy your share outright

We are 50:50 that means no maintenance but we halve all large cost. Back to school, dental etc etc

I assume the savings will go on house deposit and furniture and a car for work.

You won't get universal credit as you have to much in savings

That is plenty to live on. You say you need to buy a car as the family car is needed by your ex husband. Are you a Social Worker? Don't know how you would manage to do that job before the split, without good access to a car. I know - not the point of the thread.
Sorry I suspect your thread is to draw attention to the fact that you can earn £46,000 and still top up with £424 UC.

The maintenance calculator is wrong - there are many threads about this. You could some if established as the part parent but unlikely if it's a true 50/50 arrangement.

We just organised it that I got the child benefit and he paid for school uniform and sports and we did 55/45 split over 3 weeks I had them 1 day more.
it worked really well

@Therewegothenplease don't rely on the CMS calculator if it will be a clear 50/50. There have been several threads on here with awful outcomes where OPs have been adamant they must be entitled. As a general rule with 50/50 neither parent is liable for CM although I think this can be varied by the court if one parent is a very high earner.
Many men go for 50/50 to avoid paying CM. And as it's based on number of nights rather than 24hour periods they often do much less in practice even with 50% of overnights.

That’s weird, I thought at 50/50 here didn’t have to pay maintenance.

Did you put 50/50 into the calculator?

If he does pay maintenance then he’s not required to pay toward childcare on your time.