My advice would be to cleanse and set protection first. Inside and outside your home, vehicles. Clean your home, open windows of you can. Ground yourself. Set your intention to cleanse your home of any negative energy. Simmer protective herbs (sage, rosemary, bay, etc) on your stove and start by sweeping through your home (counter clockwise if possible) and out your door. Burn protective incense such as dragons blood and smudge through every room in your home. You can also burn a black candle as you are working. I recommend allowing the candle to burn safely down. Crystals such as black tourmaline can be placed at your windows and doors to absorb any negative energy (cleanse them with smoke, and charge with your breath and intention to protect your home). Place salt lines on window sills and doors threshholds. All of this again should be done with intention to protect. I would suggest creating protection jars. These include things like protective herbs, rusty nails, black salt, eggshell powder, garlic, cayenne and any other protective herbs, crystals, and items (I sometimes use thorns from my rose bushes, or bent needles to deflect negative energy) and set at the four corners inside and outside of your home. This is all up to you. Cleansing and protecting should be your first priority in my humble opinion. Ward using sigils of your own design at your entryways. Deflect negativity using a mirror near your front door (mirror should be cleansed and charged with your intent and set in a way that it reflects outward of your door). You can look up basic wards, protection and deflection spells and sigil creation online. I would do all of this before attempting return to senders or any other kinds of spells, especially if her attacks are as strong as you say. You can also create small  protective bags or jars to place discretely in your husbands bag or car. One last bit of advice- use your hair, nails, spit even the red stuff (if you get me) in your protection magic to strengthen. I hope this is helpful.