I'm at the end of my rope. Any advice on what I should do?

The caregiving arrangement only works if it works for both parties (the care receiver and the care giver). It is obviously not working for you. You must say no to the current arrangement. You and hubby are orbiting around your parents on the pretense that they are "independent". They aren't. It may be more comfortable and productive for you to start with them. Tell them the truth about the impact it's having on you. Also be sure to tell them that your FIL will be leaving your home also, so that they don't get jealous (this is a thing that happens regularly in families). You will need to present options to your parents and FIL so they don't freak out or feel overwhelmed and then seize up. The best option is for them to transition into a care community local to you. Preferable have all 3 of them in the same facility. Will your husband agree to move your FIL out? If not, this is an issue that needs to be resolved. Your parents and your FIL will not like this change, but don't let that deter you from moving forward and protecting yourself. Providing suggestions for solutions will help even though it's not your job to do it, but it will help you as well by expediting the process and removing any reasons for them to resist. If they do resist, you will need to be firm in your deadlines for ending their care. All you can do is warn them (if they can cognitively understand the warning). FYI you're not a "bad" person for wanting out of this arrangement...it would crush anyone.

I agree with Geaton777, your FIL needs care outside of your home. I don't agree that your parent's need to be moved into care. They are a separate case than your FIL in your home and that needs to be evaluated differently.

My first suggestion is to figure out your own self-care. I would contact a socialworker or support group to figure out local resources and your self-care program. I meet with a socialworker every few weeks to talk about stressors and self care.

My next suggestion is to think through what are doable first steps to change your situation so that you can devote more time and energy to self care. (Ahhhhh, I think I will take my own advice here and do the same! :-)

My mom lives with me. She and I talk about her moving into care at some point soon. We talk about it as a way for her socialize with other people closer to her age and as a way for her to have more of a sense of independence. She doesn't like having to depend on me and my husband and it makes her feel like a burden.

We talk about how my home is her home too and that she will be visiting me for long weekends and occasionally for a week at a time. This is what works best for me because I need the break from caregiving but I also want to remain close to her.

My husband and I both are taking care of my mom. Its my primary responsibility and I dont have a job other than taking care of my mom. It's still borderline too much work.

Are you able to hire someone to help you care for your FIL? Who takes care of him primarily, you or your husband? If it is you, does that work for you? Personally, I would find it very difficult to care for my in-laws. I've decided I wont do this for anyone other than my mom. It's hard enough with her and we have a close relationship. Personally, I wouldn't advise that anyone takes care of their parents or in-laws unless they already have a close and respectful relationship. It's too hard otherwise.

Take control and organize, establishing days and times for each parent and for tasks, as well as time for yourself.    I know how difficult this can be, as it requires a lot of anticipation and planning, but it's worth it to create a flexible schedule.   

As to the problem solving, perhaps you can set aside a specific amount of time in the morning to address problems, or in the evening after problems have occurred.  Do so over dinner, or tea, or coffee, but in a relaxed environment to remove stress as a factor.   Identify the solutions, then also designate specific time for them, as well as alternates to the plans.

This is one of the things that I think affects us all:  things happen, schedules are changed, issues addressed, and plans collapse.    Prioritization helps, as not everything is an emergency.  

Start by listing the problems, complex and urgent to those that are less so.    If you can have brief discussions on the issues, do so, and if you can get your parents to help identify solutions, that's even better.    Finding a way for them to take part in the process of problem solving helps them stay involved as well as appreciate the efforts involved.   Turn it from your problem solving to a joint one (I'm assuming your parents are still capable of participating in this?).

This isn't going to happen overnight though.  Just start with a simple problem, discuss it, identify solutions and when and who can implement them.  Then keep adding, as if you were an employer and you're identifying work plans for the week.   Bring in the caregivers as appropriate; they're probably a part of the solution as well. 

But do prioritize; don't take on everything at once.   And do make quiet times a major part of the day; not all problems are priority, so take advantage of those that aren't.  

Thank you both. Your answers have been tremendously helpful.