I know an IEI-SEI pair who seem happy together. The SEI has a twin SEI brother so perhaps she felt drawn to
someone similar to her for that reason. I could see myself ending up with an SEI and it lasting. I feel very attached to SEIs quickly and I wonder if that is something which would translate to a potentially long-lasting relationship. Both my parents are si types. I get the feeling that lookalike pairs can go through rough patches but often see it through and stay together. The way socionics descriptions describes this relation seems to suggest something similar. Seems like it could be a safe bet ITR for someone looking for stability.