You have pieced together a time frame and it is worthy for putting it all together but please don't use it to try and figure out her MLC stage. It will destroy your morale. Much of it sounds so familiar--distance, sleeping on the couch, etc... it is easy to see in hindsight but difficult to make sense of while it's happening.
Sexual abuse as a child plus seeing her step dad sick may have been the nidus for her MLC to soar. Has she been through counseling for that?
IMO, the best thing you can do is detach and show her a life without you.
I have snooped in the past as well. It is difficult to stop but you must stop completely if you haven't already. It will ruin you emotionally and some forms are illegal.
Given the information above, I would also suggest getting tested for STDs.
Congrats on your new job! You're making strides. Keep up the good work.
