Just block that person if they can't accept your boundaries. When they're blocked, they can't comment on your notebook entries or discussions and can't send you private messages.

Boundaries are often set by cultures. Some people behave more aggressively and seem pushy, but they may not realize it themselves. If you tell this person you are not interested in talking to him very clearly and tell him to quit contacting you, then he should get the message. If he doesn't, and you still want to remain on the app, then see if there is a way to report his behavior or block him. Your husband may say you are overreacting (as a practical matter) because he doesn't pose any danger to you, but if he is spoiling you fun on the app, then I think you have a right to be upset. Good luck.

How to block someone on Skype:

I have no good answers. Do not ignore your feelings.

Capture copies of the persons messages, with dates and times, and save them.

Try blocking the person on italki.

You can block people in Skype, I've forgotten how, but block him on Skype as well.

Maybe if the person is unable to get any reaction at all from you, they will eventually get tired and stop.

Get ready to change your email address and any other contact information you've given this person... don't do it, but start putting together a list of online accounts that need to have your email address, and will need to be changed or updated if you change your email address.

I agreed with you, we need to respect boundaries. Tu eres muy valiente y mereces todo el respeto.