How to have a good relationship 101:
Here's your defense against cheating.
One. Screen for women who don't have the propensity to cheat, aka, women who are not always looking for greener, shinier things.
Two. Make sure that the value, the you that you have on the table, is real, it's you, so it can remain there without extra effort on your part. Make sure that whatever you are, keeps getting better, truer, stronger. Whether or not you are with a woman.
Three. Have a great relationship. What does that mean. You lead, she's free to follow, or not. Pay attention.
You lead. Which means, you initiate, you go first.
She's free. Which means, there's no control, there's no threat, the only value on the table is, that's what's on the table. She can move in whichever direction there is, which means, the only way she can answer with, is her feelings, as her sole compass. This is her version of, "what do you want".
She follows. Reward, which means, she gets to get what she wanted.
She doesn't. Which means, the relationship ends, here. There could be some conversation and clarification if there was a fuckup. But if she does not take what is on the table, the table expires.
That, simple.
On the male side: you lead, she follows, or she doesnt. She will also act, and have behavior, and propose things. Some will be good, for you, some wont.
So you reward, or accept, the good, and punish / push away, the bad.
The relationship is what is built in alignment.
With your leading, and she following, responding.
Your defense against cheating:
Have a good, relationship.
The higher the aim, the higher the quality.
The higher the quality, the more durable.
You cannot pay, control, coerce, regulate, quality.
Replace your relationship with a regular friendship if it's not obvious already.
Have a good relationship.
Have a great one.