This is an extremely easy solve, sit down with your wife and explain to her that you are feeling a loss of connection and important time spent together.
If you are her wife and he is her boyfriend than it should be an easy conversation since the marriage would naturally be a priority for any loving reasonable person and any loving wife would happily listen to her husband's valid concerns and take steps to feel connected and ensure that those moments arent lost between the two of you. If your wife really cares about your marriage shell recognize she may be spending far too much time on her boyfriend and neglecting important moments in her marriage and take steps to remedy that.
Honestly I'm not sure why you two decided to get separate bedrooms, that seems like a step backwards to me in a marriage. I understand a separate bedroom for non primary partners to spend the night in, but you dont need a designated bed for each person to do that. Just wash the sheets afterward.