So following a divorce there are a number of factors that affect people's long term happiness: possibility of remarrying, quality of time spent to kids, amount of income lost due to childcare and amount of income paid to ex-spouse, and so on.

We can assume overall these tend to impact men and women differently, with for example women tending to get more access to kids but losing income as they spend time on childcare, and men tending to pay more to their ex-wives and losing time with the kids.

You argue that women gain more from divorce than men overall as women are the ones who file for divorce in the majority of cases.

Let's accept for the sake of argument that women do relatively better out of divorces all things considered. The explanation for this could be good post-divorce outcomes for women, which are the factors above such as ease of remarrying or custody. This is what I see as the core of your argument.

An alternative explanation might be that in a bad marriage, women are in a particularly vulnerable position relative to men. In that case even with worse outcomes from divorce for women, it might still make sense for women to file for divorce more often.

I think it would be hard to find convincing evidence either way. But it's plausible the tension may just be apparent and there is another explanation.