Everyone comes into a relationship with a certain amount of baggage. Divorced people tend to have more of this than those who are simply moving from one dating relationship into another. Many divorced people go on to have new, healthy and mutually enjoyable relationships. However, some people also try to enter into new relationships before they are really ready. If you suspect that your boyfriend still harbours serious feelings for his ex-wife, it is a good idea to consider the situation before your relationship becomes more serious.
Pay attention to how much he talks to her or communicates with her. Consider other factors such as children. Remember that if a couple shares a child, there is a much more valid reason for them to communicate often, therefore ongoing and constant communication is something you have to expect.
Evaluate how much he talks about her. People who can't stop talking about their ex often have lingering feelings, or at least issues with the relationship that are not yet resolved for them.
Note if your boyfriend hides things from you or won't give you a straight answer to a question about his ex. Don't overreact based on him avoiding a question about his ex alone, as he may simply be uncomfortable discussing it. Worry more if you ask a straightforward question about his feelings for her and he won't provide an answer.
Talk to your boyfriend about his feelings for his ex. There is a difference between loving someone and still being in love with them, and it is important for you to understand his feelings towards his ex-wife. For instance, a man may love the mother of his child without being in love with her.
Speak to a counsellor or relationship therapist if your boyfriend is willing and you are still having issues about his perceived feelings for his ex-wife.
Try very hard to sort through and identify what the real signs are that signal your boyfriend has feelings for his ex-wife, and those signals which are only being interpreted as problematic due to your own insecurities.