Do I get a pass to cheat after my bf cheated?

I know it sounds petty but do I get a pass if he cheated? We had been together a 1.5 yrs and those last few weeks before he cheated was the best we ever had. We usually had a lot of arguments and break ups but he cheated when everything going so good and calm. He spent like 3 days over at mine where he even got along with my teens and we had zero disagreements with lots of time in bed too. He left mine and took a random one of his old friends home he seen on the way home and cheated few hours later.
Next day he admitted it on the phone. I tried to sort of see other people because he just wasnt putting enough effort to make up for it. I met up with someone and we only just made out for ages. I told my “bf” about it and he wasnt too happy. Anyways fast forward 3 months I’m 11 weeks pregnant, we are trying to sort of work it out. My pregnancy hormones are all over the place, I literally always think what if he is cheating again and ask him a million questions so he knows I don’t fully trust him yet. Now I’m thinking will my raging fear of him cheating again end if I just cheat too? If I be petty and get revenge? Did this work for anyone else?