Op I think this has been well covered off by most posters already.
Firstly, bottom out what is causing resentment and tackle it. Whilst the transition of moving from mat leave to work is stressful, the reality is that if you are the primary breadwinner, then he has to step up domestically. Not doing so is not an option.
That means carving up chores and making it super clear what he is in charge of, consistently, week in week out.
Second of all, try not to compare yourself to other families and households. It’s a complete black hole and this is a marathon, not a sprint. None of us know longer term how individual family set ups will play out in 10-15 years. It is a constant juggling act.
Finally? I understand the resentment and it’s why I’m saying please tackle it. I have just ended a serious relationship, I earned significantly more than my partner and whilst we never cohabited permanently, we had stints of him spending significant lengths of time in my home. Tester if you like. The money disparity didn’t bother me in the beginning, I had more so I was more generous; weekends away, nicer restaurants for dinner, indulgent presents for birthdays etc.
What started to bother me was the lack of effort he consistently bought to the table. If I had ridiculously stressful/ long weeks at work (but equally that job afforded him a slightly nicer lifestyle as a result), i expected him to both appreciate that and bring other things to the table: in the main, practical help. If he had done something as simple as saying ‘I can see doing xyz consumes some of your time each week, why don’t you let me take that on and take it off your plate’, it would have made the world of difference.
But he didn’t. I would work ridiculously hard, then come home and have chores to get done and he would be utterly content to essentially sit there and let me crack on. So in my mind he got the benefits of being with me but bought very little to the table himself. And what would have been worth it’s weight in gold would have been very real practical support domestically.
It wasn’t the only reason I called time on the relationship. But it was a significant factor. I can completely accept someone not earning what I do, but if they are happy to take and benefit as a result of my hard work - how is that being reciprocated?
Work on that with your DH. Because IME, if that resentment beds in it can become extremely corrosive in a relationship. Stress of young children in the mix makes it so much harder. Talk to your DH and ask him to step up.