
I had an ex that was allergic to everything. It takes a lot of work cleaning things off if you have a pet. I could not say the allergy is the dealbreaker in itself, but if it is someone that is not willing to work with you/compromise regarding their allergy, that could be a dealbreaker. Maybe talk to them about what pets in general (especially if you want one/have one).
it definitely is (I mean, how would you feel about being rejected due to your own hardships being viewed as like, “not worth the trouble”?), but far less harmful to him in the long run than if you tried to follow through on dating him when you already know how reluctant you would be to accommodate his survival needs