AITA for telling my MIL I’m having an affair with her grandson?

So I (30f) have been married to my husband (31m) for ~3 years, we’ve been together for more than a decade.<br><br>After years of being told we couldn’t have kids, we announced our pregnancy super early because we thought it would be a miscarriage (we’ve had 3). <br><br>She’s always been clingy and intrusive. When my husband said I wasn’t feeling great for a few days she insisted on coming over and cooking. I said no because I didn’t want to risk her bringing COVID she said she’d promise she was safe then still showed up at the door and tried to get in. We were angry, but she wouldn’t leave until my husband’s brother came over and got her.<br><br>Her: I can’t believe my own son won’t let me in his house. You’re horrible.<br><br>Brother: She’s horrible, get used to it.<br><br>Since then she’s been insinuating that I’m going to be an unfit mother and she knows our marriage is troubled. She’s told me ‘divorce is an option’ and that she just wants what’s best for the baby. This went on for over a month. <br><br>Then she said my husband had called her crying and said he was unhappy with our marriage. I asked my husband about it, he said it wasn’t true. She told me she was worried about our marriage because of my bad karma. I snapped. I told her we had an agreement that I could sleep with her son and she could stay out of my marriage. <br><br>She said she couldn’t believe I’d say that about her sons and started listing off names. I said I only meant one and talked about how big his dick was (it’s average), how good the sex was (it wasn’t), and what he liked (I just made it up). I also told her she was being unbelievable, calling my husband gay, and that I only slept with her son because I wanted to hurt her and she was so unphased by the possibility of her son having an affair that the only way I could hurt her was to describe the sex. <br><br>She called my husband immediately and told him. He was angry and asked what she meant by her sons. I guess she just shook her head and refused to answer. I told him that the problem was her, not me. She was calling me a whore and telling people I hated our marriage and wasn’t going to be a good mother and that was not only making my life worse but also messing with our relationship as a couple. I also told him I wanted her to see my side of things, we had a huge fight. <br><br>Her son is calling me, texting me, messaging me, showing up at my house. A lot of people are saying we’re having an affair. I’m sick of having to deal with this and my husband is blaming me 100%.