In Islam, there is nothing wrong with the current situation, and his reason is completely valid, compassionate, and responsible. However, on a personal level, the answer to this question depends on the answers to a few additional questions:
1. Is the first wife happy with this situation or does she wish to be given her “freedom”?
2. Is your husband happy with this situation and feel it is the best thing for the family?
3. Is this first union causing great harm to your marriage with him?
There is nothing inherently wrong with someone remaining married without “love”. In fact, the way we define love is usually very narrow. Many people define “love” as that wonderful feeling of passion and adoration that happens when you first meet someone and “fall in love”, or that feeling you have for someone you want to often be with; a feeling that leads to a physical desire for them.
However, love can take many forms. Of the many couples I have known, I don’t think I have ever seen one pair have the same kind of love as the other. Some couples remain married into old age but continue more as friends than as lovers. Some even lead almost separate lives, but there is a feeling of mutual respect and comfort they enjoy by staying together. Other couples grow to feel more like they are siblings than husband and wife, and feel very protective of each other, but no longer feel passion. Some couples feel love for the other one as a confidant and a best friend.
Some feelings that keep couples together cannot even be defined as love. Some of the reasons couples stay together may be out of mutual respect of their history together and the deep connection they feel through that, or out of compassion for another who needs their company, or many other reasons. If you survey the couples you know, you will find that most of them are not together simply because of “love”. There are other qualities that are noble in relationships beyond love, and there are other kinds of love.
There isn’t any problem with him remaining married to his first wife without “love”, as you define it. However, it sounds like the situation may be upsetting to you in some way, therefore, you may want to explore in yourself if there are other reasons why this situation upsets you.
Disclaimer: The conceptualization and recommendations stated in this response are very general and purely based on the limited information provided in the question. In no event shall AboutIslam, its counselors or employees be held liable for any damages that may arise from your decision in the use of our services.