Many men love more than one woman at the same time. For example, a man might love his mother, sister, wife, and daughter -- all female -- but the type of love he feels for each of them is radically different. What you seem to be referring to is love of the romantic variety.

People can romantically love more than one person at one time but the odds of them doing so successfully seem to be quite slim. Given your stated confusion, my guess is that you're already in a committed partnership with someone you deeply care for but you find yourself attracted to and caring deeply for another woman.

People who have multiple romantic partnerships are typically referred to as cheaters/adulterers or more rarely, polyamorists. The critical difference seems to be whether or not the two women you are in love with are both aware that you are emotionally/possibly sexually intimate with another woman and are accepting of that arrangement. If they are, you're probably a polyamorist; if they're not, you're probably a monogamist who would be considered a cheater/adulterer by most standards within this culture.

I've observed that in some men their ideal woman is split (i.e. madonna/*****) and thus, so is their romantic attraction to women. You might find it helpful to read up a bit on anima projection. In nearly all cases, unless you are in an established polyamorous relationship with both women, an affair will nearly always have disastrous results. For that reason, it may be helpful to seek out a therapist who can help you sort out your feelings of tangled attraction, emotion and conflict before you go any further.