This is adapted from advice I have given many times to people who are about to be interviewed on TV news (I work in media/broadcasting) and I think it's pretty applicable to keeping frame with women. Here are two good rules of thumb to help avoid verbal diarrhea and saying things that immediately make you cringe.

Remember this phrase:

Don't elaborate, and don't speculate.

The first means if you have said something clearly you don't need to add extra verbiage. If she asks if you were cheating on her you can say "No" and just stop talking. If she asks you if you like her or some other insecurity test you can say "Yes I like you" and stop talking. I see a lot of advice here where people recommend wordy or too-clever ways of phrasing something when a simple yes/no or factually corect answer would suffice. Say what you mean to convey and don't elaborate or explain. It can take practice but try to use this principle always.

The latter is even easier to get into your head. Stop talking about hypotheticals. If you're talking about what might have happened but didn't happen you're probably wasting your time. Like if someone is yelling at you because you didn't pick up the phone and says "what if I was in the hospital" you answer "but you weren't" or just refuse to engage altogether. And don't engage in speculation yourself, don't guess how you will feel in the future, don't talk about what you would do if X or Y happened, don't ramble about how things would be now if stuff had happened differently. It's a waste of time, conduct your discussions by remaining focused on things that are real and in the present.

It's often not what you say but how you say it. Remember not to elaborate or speculate if you want to be perceived as clear, direct, and powerful.