When a married person cheats, why would you blame the person they cheated with?

An example is if a married woman sleeps with another guy, that guy she slept with would just laugh it off and brag about it.

It won’t affect him at all.

It will only affect the married couple. The man and the woman. Because they live in the same house and own property or finance together.

They should just blame each other

I’m only asking this because when I was 20 in 2014, I was dating a married man, although we never had sex, he was offering me coffee and food and I just tagged along with him.

I also kissed him and touched his erect penis after as he told me to. I did feel uncomfortable doing it, but I did it anyway.

I was 20 and naive and had a low self-esteem

He’s the one that should be respecting his wife and child

Why would people blame me for it? He was also older.