This is something I worry about as well. When I was younger, I definitely had a type; dusky skin, dark hair, almond shaped eyes, I had an attraction towards latina girls.
When I met my STBXW, she didn't fit all of those bits, but I found her stunning. Very fair skin, lighter eyes, still dark hair, but much more petite that the other girls I had been interested in (I had never gone after heavy girls, but my ex was positively skinny).
Now, when I'm looking at women, I find my attraction goes towards those that fit my STBXW's physical characteristics; fair skin, slender build, dark hair, etc. I can still appreciate the attractiveness of women outside of those characteristics, but they don't hit the buttons as hard at that specific type do.
I think the thing is that we tend to have preferences, and if our waywards/exes check those boxes, it doesn't necessarily mean that we will no longer be attracted to those types of people. Rather, I think it means that we will tend to look for people with those characteristics because we find them attractive. It might have a bit of comfort via familiarity, despite the negative associations we have with someone who looks like the one that hurt us.
I am going to let myself talk to a multitude of people before I try to find a partner to settle with. I am a very visual person; I worry that I will not be able to fully engage in a relationship with someone I'm not extremely attracted to. That wouldn't be fair to either of us; whoever I am with will deserve to have someone who is fully engaged, and I deserve to have someone I can fully engage with. I was talking to a friend of mine, and she asked what, specifically, I was looking for in a partner, and I mentioned that one of the requirements I had was that I needed to be able to picture myself being enthusiastic in bed with them.
If I couldn't do that, then it wouldn't work out, because I refuse to have another relationship that is dead in the bedroom. All of the rest needs to fall in line as well - shared interests, sense of humor, pleasant disposition, and a passion with and towards each other - but attraction plays a huge role for me.
Now, long anecdote aside, I am assuming it does for you as well, since you found someone who looks very similar to your ex, and I am assuming that you found your ex attractive. Nothing wrong with that; there was a reason why we started relationships with our waywards in the first place, and a reason why we stayed committed. Not just physical, of course, but most of us were/are still attracted to our ex partners. I know that I am, physically still attracted to my ex, though morally, ethically, and personality-wise, I find her repugnant.
I'd give it some time. Get to know this new guy a bit more, see how he differs from your ex. See the ways he is NOT like your wayward. Build him as a complete and unique person from the cheating guy who just happens to look similar.