Though based on life experience, I would suspect most breakups and divorces are the man's fault, be it cheating, abuse, etc.

However:

There has been some interesting data on lesbian divorce. https://muddyum.net/todays-moment-of-duh-high-lesbian-divorce-rates-e20fddb3f4f5

I have theories. For instance:

1. Societal brainwashing means men enter marriage with low expectations, while those of women are unrealistic. Two people who expect a lot from a marriage sounds unworkable.

2. Lesbian couples are less likely to have a partner who is very dependent on the other, as in many (especially conservative) marriages.

3. They're generally less likely to be conservative, meaning divorce isn't as negatively viewed.

Do women sometimes bail out of a salvageable marriage? I'm 100% sure that happens, at least occasionally.

Do men bail out to change partners/trade in for a younger model? Also 100%.

The reasons I put most of the blame on men include (a) men are shit to women far too often, (b) members of MAGA and the Manosphere are (rightly) no-go zones for many women, and (c) the evidence at hand — as women gain more choices, marriages decline. The causality isn't definite, but it at least appears they were marrying because they felt they had to.