Hi PeppermintTea,
I wasn't married to someone with BPD (I'm here because my SO has an uBPDxw) but was married to an alcoholic so in many ways I had similar issues. I have described my marriage as me and my 2 sons (1 husband/1 son) I was the only adult in the house and it was exhausting. Wrongly or rightly I put most of the energy I had into my son and towards the end of my marriage I didn't even put much there due to my own depression... .I was not taking care of myself so could not take care of anyone else. Sick as this is I was actually excited about having a hysterectomy because
finally someone would have to take care of me for awhile!
I agree with Mutt self care is really important so you don't become overwhelmed and exhausted. Even more important because you have 4 kids in your house so you are totally out numbered I can hear you now... .but I don't have time for that! I have to take care of everyone else. It's important to make time, maybe just a 30 minute walk (alone) just to have the space to think and get your energy level up, maybe you go to bed 30 minutes earlier than usual and read, go out with your girlfriends... .whatever floats your boat
Regarding the kids how about you try something like carving out sometime each day for one child to give them your undivided attention... .do something with the 3 year old one day, 4 year old the next day, 11 year old the next day and 13 year old the next... .take the kids for walks get out of the house, get some sunshine, and talk to them (practice your validation skills) I bet you will start feeling more connected to each other or maybe with the younger ones read to them or take time out to play with them.
Just know you're not alone many of us struggle with balance in our lives too.