Developed an Interest in My Neighbour

OP, it's very clear from your previous thread that you have compulsive tendencies and tend to fixate on people. I'll reiterate the advice I gave you in that thread - you need to do some major work on your boundaries (or lack thereof).

I'll leave it at that, as I somehow doubt you're going to take any of the advice you're going to get on board.

Assuming the partner you refer to in the first line of the OP is the same partner you referred to in your previous thread, you have some very serious reflecting to do on the way your actions are affecting him.

You are cheating on him. You can dress it up whatever way you want, but you know full well that if you really believed that he wouldn't have a problem with your trysts with the neighbour you would have told him about it before now.

He has put up with a lot already. You need to be mature and sit him down for what might be a very difficult conversation. Take responsibility for your actions and see if he wants to work through this or if it's the last straw. No begging or excuses.

Have you told your partner that you are meeting this other man and kissing him and cuddling with him in a bed?

If you were sure that this wasn't cheating you wouldn't need courage to be honest.

Completely apart from the betrayal of your partner's trust, you need help. You have a pattern of poor decision-making in the context of obsessive relationships.

There is something very amiss with you that is behind your decision-making. You need an outside perspective on it, or you will continue hurting people close to you.

Think about how hurt you were when a mere acquaintance didn't spend enough time with you. Now imagine how hurt your partner will be by your actions. I'll say it again: You have to be honest with him, difficult as it might be.

OP I think some therapy might be badly needed here if you think lying in bed with another person kissing away while the boyfriend is clueless is beyond belief IMO.

I was more referring to this "Unfortunately I do have a tendency to swap obsessions, usually between people.

I would become obsessed with one guy (not necessarily sexually, it could simply be friendship-related), then as that decays or becomes old, I find another to become obsessed with - and the cycle continues." about needing therapy the rest is just wrong IMO.

In the 13yrs together, have you & your boyfriend ever brought anyone else into the relationship before?

If not, then I sounds like the comment of him watching you have sex with another guy was just a harmless fantasy. No harm in that. But you took it upon yourself to make a move on the neighbour - which is straight up cheating.

Kissing (definitely), or even just flirting messages to another person while in a relationship is cheating, however much you may try to downplay it.

If it is something that you both have done before, then I still think you crossed the line by acting on it without your bf being involved. I don't think he meant for you to go out and test the waters behind his back before maybe then asking him to join in the fun.

Ask him and see how that conversation goes down.

"Either way, and irrespective of his response, I want to continue meeting the neighbour."

I don't care who I hurt, I'm going to keep doing whatever I want.

So why start a thread here?