To think that DH should also do some form of flexible working?

Sounds like he’d rather work than parent. I hope you have the same amount in your pension as he has.

Neither of you are being unreasonable, you just have different opinion on the desire to save the money.

Flexible working can be brilliant, but it can also be very stressful and sometimes the extra money just isn’t worth the weight on you. You could start off with the extra childcare and see if you start to really feel the financial pinch and then revisit the conversation. It’s easier to cut the childcare if you need to, rather than your husband flip flopping on flex working requests which might not be permitted.

You being (very) more senior is probably why you've been granted it. Do you not trust DH to know his own workplace? In all honesty if you can I'd pay for the childcare and start looking at school hours and fitting both your working patterns to that. Even though you're allowed 2 requests a year it's much better of you just do one.

Men find it very very hard to ask for the flexible working IME. I pointed out to my DH that the feelings of fear and worry over not being taken seriously were the same for women and most of us have to confront it in our 30s because of children and mat leave. So he's had 10 years more than me of being able to prioritise his career.

Men also feel more pressure to be the breadwinners and in some nasty old fashioned work environments genuinely are judged harshly for even asking. So you and DH have to show each other kindness and try several approaches- maybe do the childcare but he also puts a marker down and asks for flex. The flexible need only increases as they go through primary school.

Do you work for the same company? Because I don't see how you being able to means anything for his situation if his boss isn't okay with him doing it. You've said you're in a more senior position, and honestly that seems to be the situation where people get the most flexibility.

I would say does he generally do his bit at home with other things or are you running the show… if the latter he needs to step up. I think he should at least ask his employer. I’d want to be quite sure it’s not your DH who can’t be bothered to pull his weight in parenting / family life.

Go for childcare

Depends. Do you have a feel for whether he’s telling the truth about his boss? Seniority = nothing to do with it. In fact I would say more junior staff have heavier in office expectation a lot of times. Some bosses truly are awful also.

If he’s truthful and it’s £350 for 6 months I’d suck it up rather than add stress to what will already be a big adjustment period. I’d tell him to job hunt though as such lack of flexibility not ideal for a parent in a secondary income role, really.

If being untruthful he needs to massively wise up.

I don't think your husband is being unreasonable. Make your lives a bit easier and pay for the extra day childcare.