Of course. Whether I'm talking to both of you or 1 of you, my number 1 priority is communication between the 2 of you. My advice and guidance will be more accurate if I'm talking to both of you but I'm happy to assist you alone if you feel that your partner wouldn't be willing. There's obviously a moral issue if you're discussing your private lives with someone without your partner's consent. If I feel that discussing with just 1 of you would be doing more harm than good from a trust or moral perspective, I may refrain from further guidance.
The first thing would be to make sure that he understands what you want from him. It's possible that he may just need guidance and coaching which, as a dominant male myself, I can offer. If he has no desire to be dominant and possibly you're both submissive, there are other options to achieve what you both want from sex. We can discuss those and find out which options suit you both.
This is really common and not something to freak out about. You're going through some emotional trauma in response to your wife's infidelity, it'll take a while for your thoughts and feelings to stabilise but they will. Obviously, cheating is not ok and being turned on by it shouldn't affect whether you choose to forgive or not. You do need to choose whether you want to pursue your new found fantasy or not though. If you nurture it by jerking off, it will make it more difficult if you later decide it's not for you. I can help you both through whichever route you choose to take.
It is true that some (if not most) women enjoy being submissive and dominated. This can often involve being on their knees and worshipping a cock like you refer to seeing in porn. We would need to discuss and experiment with how your wife feels about submission and whether you can develop the dominance she needs from you for her to want to submit to you like that.
Firstly, we would need to assess what you both want. If he's not initially open to the idea of you being with another man, we should explore other ways of him being able to sexually satisfy you. If he's still unable to satisfy you after trying everything he can, he may become more open to the idea of another man because of his love for you and because he cares about your satisfaction. Ultimately, you shouldn't expect him to allow you to fuck another man, that's not a reasonable expectation of anyone but I'd say that there's a good chance we can find a way of getting you the sexual satisfaction you need, one way or another.