I believe infatuation is blind. Most relationships start off with both people attracted to one another and doing everything possible not to "blow" their chance of exploring this chemistry they feel towards one another. The word "no" is seldom if ever heard in the (infatuation phase) of a relationship.
When a person starts to "see" major flaws or things they dislike but decide to continue to stay in the relationship it's not because "love is blind". It's reflection of their inner self at that point. Maybe they don't think they deserve better or believe they could find better, they're tired of starting over in new relationships, or they stay because they want to prove everyone wrong who warned them. This is about having low self-esteem which prevents them from having "deal breakers".
Generally speaking the phrase "love is blind" implies this person (doesn't see) any flaws, doesn't feel they're getting the short end of the stick, and refuses to listen to anyone who dares to attempt to point out any negatives. Love is blind is right up there with "ignorance is bliss". Very few people however are "blind" in any long-term relationship. Facing the facts means they'd have to make a tough decision. Therefore they (choose) to look the other way.
There are only two ways to experience joy and peace of mind in relationships: we either get what we want or we learn to be happy with what we have.