So one of her recent remarks was "We need to re-connect" and she also mentioned that we could go to get MC. Shall I bring it up again and say "how can we re-connect when you are connected to OM?" Is this a boundary or an ultimatum?
It's neither a boundary nor a threat. It's passive aggressive behavior. You are implying your aggressiveness but through a passive question. Huge no no.
Threat:
you better not talk to OM or I will leave you<-- not effective and sets you up for her to challenge you.
Healthy boundary for YOUR mental health:
As long as you are talking to OM, there cannot be a relationship between us. If you continue to talk to OM then I cannot be a part of this marriage.
As Sandi said, it's not a question it's a statement. It tells her clearly what you won't accept for YOURSELF. You aren't controlling her by saying "stop talking to OM" you are only asserting what you won't put up with in your life, and what YOU will do if YOUR boundary is overstepped.
You are giving her the power or the option to change her behavior if she wants the positive outcome. But if she doesn't, you are protecting yourself from further damage.
Start with small ones like Sandi said. Ones that don't force you to do something you are not ready for yet.
Like:
I will not sit with you while you chat on your phone to OM. If you continue to chat with OM I will leave the room/house.
This may be a bad example because ideally you tell her she needs to step outside to even message him. She's not to have chats with him while in the marital home, out of respect for your daughter and to the sanctity of your home.
What other boundaries do you have? What behavior will you not stand for in your life?
Me, H-34 now 38 W-32 now 35 T-13 now 18 years M-6 now 9 Daughter 3 years now 7 Bomb 11/27/12 - OM 1 year in house separation Reconciliation 12/2013. Healed now 2017