DoingThingsWrong - I am a BS, and unfortunately as much as people say there is a "cheater's handbook" there really isn't as clear of a BS's handbook. How to Help your Spouse Heal is helpful, but we are all different. For example, my reaction was nowhere near GMC's in this thread.
As such, take my advice or leave it as I am not your BS.
I would start by telling your BS some semblance of exactly what you posted. And tell her some of the responses that you got on here and what you think about them. TALK TO HER - about your frustrations, about your feelings, about whatever. The fact you are posting on here tells me that you do care about the issues you are having, but it's easy to convince me as I'm not your BS.
I am not as on board with the "you are using ___ as an excuse" as other posters - I think you can use these statements as an opportunity for change.
Yes, mine was worried to as I was no longer safe. Its scared me that I wasnt able/unwilling to see the signs I was shutting down.
I do not advocate for your BS becoming the gatekeeper, but, you could turn the above into a positive, but you have to make a deal with yourself. Tell your BS to communicate with you when she feels like you are shutting down (it sounds like she has been willing to do this already so hopefully she would be willing) AND decide that you are going to talk to her in that moment. Do not break this deal with yourself.
Better yet - don't make her be the gatekeeper at all. Set a time - 15 minutes - 30 minutes - whatever - and stick to it (I'm a goal setter so ascertainable rules about time/place/manner work for me - maybe not for you). Don't let yourself back out of it.
I don't care if you have to preface those moments by qualifying them with something some would deem an excuse. Say out loud "I'm really tired right now so this may not be my best discussion ever" but then talk anyway - don't give your self a reason to stop. Being tired isn't an "excuse" per se - it's a fact. But, if you say you are tired BUT you are still going to talk - that SHOWS your BS that they are worth it to you - they are important enough for you to be tired AND keep talking. To me - that is worth it's weight in gold and then some. That makes me feel worthy, important - and ultimately safe.
Maybe that's where you should start from for awhile - use whatever reason you are not connecting as an opportunity to show your BS that they are more important than that reason to not talk - to not connect. Remind yourself if you find yourself not doing something of what IS important to you.
Stick to something when you say it - if you say "I want us to spend at least ____ per week just reconnecting" then don't "get too busy" or blow it off. Stick to it. Set a reminder in your phone if you have to - don't miss those chances your BS is giving you to open up. If you miss enough of them, your BS will be gone.
Connect. Plan. Stick to it. Set ascertainable goals for yourself.
Of course if every time you give some reason why you don't want to talk but are anyway, your BS will get tired of hearing that. But if you really feel that way then you have to ask yourself what you are sticking around for. If this relationship is important enough for you to be doing the work on yourself, don't neglect helping your marriage at the same time too.